diff --git a/src/index.ts b/src/index.ts
index f298417..7768db2 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,4 +1,5 @@
 import type NarouNovel from "./narou.js";
+import type { ExecuteOptions } from "./narou.js";
 import NarouNovelFetch from "./narou-fetch.js";
 import NarouNovelJsonp from "./narou-jsonp.js";
 import RankingBuilder from "./ranking.js";
@@ -67,13 +68,16 @@ export function ranking(api: NarouNovel = narouNovelFetch): RankingBuilder {
 /**
  * なろう殿堂入り API でランキング履歴を取得する
  * @param {string} ncode 小説のNコード
+ * @param {ExecuteOptions} [options] 実行オプション
+ * @param {NarouNovel} [api] API実行クラスのインスタンス
  * @see https://dev.syosetu.com/man/rankinapi/
  */
 export async function rankingHistory(
   ncode: string,
+  options?: ExecuteOptions,
   api: NarouNovel = narouNovelFetch
 ): Promise<RankingHistoryResult[]> {
-  const result = await api.executeRankingHistory({ ncode });
+  const result = await api.executeRankingHistory({ ncode }, options);
   if (Array.isArray(result)) {
     return result.map(formatRankingHistory);
   } else {
diff --git a/src/narou-fetch.ts b/src/narou-fetch.ts
index 9c162b5..425cdeb 100644
--- a/src/narou-fetch.ts
+++ b/src/narou-fetch.ts
@@ -1,6 +1,6 @@
 import { unzipp } from "./util/unzipp.js";
 import NarouNovel from "./narou.js";
-import type { NarouParams } from "./narou.js";
+import type { NarouParams, ExecuteOptions } from "./narou.js";
 
 type Fetch = typeof fetch;
 
@@ -18,7 +18,8 @@ export default class NarouNovelFetch extends NarouNovel {
 
   protected async execute<T>(
     params: NarouParams,
-    endpoint: string
+    endpoint: string,
+    options?: ExecuteOptions
   ): Promise<T> {
     const query = { ...params, out: "json" };
 
@@ -36,7 +37,7 @@ export default class NarouNovelFetch extends NarouNovel {
       }
     });
 
-    const res = await (this.fetch ?? fetch)(url);
+    const res = await (this.fetch ?? fetch)(url, options?.fetchOptions);
 
     if (!query.gzip) {
       return (await res.json()) as T;
diff --git a/src/narou-jsonp.ts b/src/narou-jsonp.ts
index 8f4ad01..7ef155e 100644
--- a/src/narou-jsonp.ts
+++ b/src/narou-jsonp.ts
@@ -1,5 +1,5 @@
 import NarouNovel from "./narou.js";
-import type { NarouParams } from "./narou.js";
+import type { NarouParams, ExecuteOptions } from "./narou.js";
 import { jsonp } from "./util/jsonp.js";
 
 /**
@@ -8,7 +8,9 @@ import { jsonp } from "./util/jsonp.js";
 export default class NarouNovelJsonp extends NarouNovel {
   protected async execute<T>(
     params: NarouParams,
-    endpoint: string
+    endpoint: string,
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    _options?: ExecuteOptions
   ): Promise<T> {
     const query = { ...params, out: "jsonp" };
     query.gzip = 0;
diff --git a/src/narou.ts b/src/narou.ts
index 5ff03ac..52f8a31 100644
--- a/src/narou.ts
+++ b/src/narou.ts
@@ -21,6 +21,16 @@ export type NarouParams =
   | RankingHistoryParams
   | UserSearchParams;
 
+/**
+ * なろう小説APIへのリクエストオプション
+ */
+export interface ExecuteOptions {
+  /**
+   * fetch関数のオプション
+   */
+  fetchOptions?: RequestInit;
+}
+
 /**
  * なろう小説APIへのリクエストを実行する
  * @class NarouNovel
@@ -35,7 +45,8 @@ export default abstract class NarouNovel {
    */
   protected abstract execute<T>(
     params: NarouParams,
-    endpoint: string
+    endpoint: string,
+    options?: ExecuteOptions
   ): Promise<T>;
 
   /**
@@ -46,9 +57,13 @@ export default abstract class NarouNovel {
    */
   protected async executeSearch<T extends keyof NarouSearchResult>(
     params: SearchParams,
-    endpoint = "https://api.syosetu.com/novelapi/api/"
+    endpoint = "https://api.syosetu.com/novelapi/api/",
+    options?: ExecuteOptions
   ): Promise<NarouSearchResults<NarouSearchResult, T>> {
-    return new NarouSearchResults(await this.execute(params, endpoint), params);
+    return new NarouSearchResults(
+      await this.execute(params, endpoint, options),
+      params
+    );
   }
 
   /**
@@ -58,11 +73,13 @@ export default abstract class NarouNovel {
    * @see https://dev.syosetu.com/man/api/
    */
   async executeNovel<T extends keyof NarouSearchResult>(
-    params: SearchParams
+    params: SearchParams,
+    options?: ExecuteOptions
   ): Promise<NarouSearchResults<NarouSearchResult, T>> {
     return await this.executeSearch(
       params,
-      "https://api.syosetu.com/novelapi/api/"
+      "https://api.syosetu.com/novelapi/api/",
+      options
     );
   }
 
@@ -73,11 +90,13 @@ export default abstract class NarouNovel {
    * @see https://dev.syosetu.com/xman/api/
    */
   async executeNovel18<T extends keyof NarouSearchResult>(
-    params: SearchParams
+    params: SearchParams,
+    options?: ExecuteOptions
   ): Promise<NarouSearchResults<NarouSearchResult, T>> {
     return await this.executeSearch(
       params,
-      "https://api.syosetu.com/novel18api/api/"
+      "https://api.syosetu.com/novel18api/api/",
+      options
     );
   }
 
@@ -87,20 +106,33 @@ export default abstract class NarouNovel {
    * @returns ランキング結果
    * @see https://dev.syosetu.com/man/rankapi/
    */
-  async executeRanking(params: RankingParams): Promise<NarouRankingResult[]> {
-    return await this.execute(params, "https://api.syosetu.com/rank/rankget/");
+  async executeRanking(
+    params: RankingParams,
+    options?: ExecuteOptions
+  ): Promise<NarouRankingResult[]> {
+    return await this.execute(
+      params,
+      "https://api.syosetu.com/rank/rankget/",
+      options
+    );
   }
 
   /**
    * 殿堂入りAPiへのリクエストを実行する
    * @param params クエリパラメータ
+   * @param options 実行オプション
    * @returns ランキング履歴結果
    * @see https://dev.syosetu.com/man/rankinapi/
    */
   async executeRankingHistory(
-    params: RankingHistoryParams
+    params: RankingHistoryParams,
+    options?: ExecuteOptions
   ): Promise<RankingHistoryRawResult[]> {
-    return await this.execute(params, "https://api.syosetu.com/rank/rankin/");
+    return await this.execute(
+      params,
+      "https://api.syosetu.com/rank/rankin/",
+      options
+    );
   }
 
   /**
@@ -110,10 +142,15 @@ export default abstract class NarouNovel {
    * @see https://dev.syosetu.com/man/userapi/
    */
   async executeUserSearch<T extends keyof UserSearchResult>(
-    params: UserSearchParams
+    params: UserSearchParams,
+    options?: ExecuteOptions
   ): Promise<NarouSearchResults<UserSearchResult, T>> {
     return new NarouSearchResults<UserSearchResult, T>(
-      await this.execute(params, "https://api.syosetu.com/userapi/api/"),
+      await this.execute(
+        params,
+        "https://api.syosetu.com/userapi/api/",
+        options
+      ),
       params
     );
   }
diff --git a/src/ranking.ts b/src/ranking.ts
index 21ec693..aea6fb6 100644
--- a/src/ranking.ts
+++ b/src/ranking.ts
@@ -11,6 +11,7 @@ import {
   Fields,
 } from "./params.js";
 import type NarouNovel from "./narou.js";
+import type { ExecuteOptions } from "./narou.js";
 import type { SearchResultFields } from "./narou-search-results.js";
 import { addDays, formatDate } from "./util/date.js";
 
@@ -108,21 +109,24 @@ export default class RankingBuilder {
    * 設定されたパラメータに基づき、なろう小説ランキングAPIへのリクエストを実行します。
    *
    * 返される結果には、Nコード、ポイント、順位が含まれます。
+   * @param options 実行オプション
    * @returns {Promise<NarouRankingResult[]>} ランキング結果の配列
    * @see https://dev.syosetu.com/man/rankapi/#output
    */
-  execute(): Promise<NarouRankingResult[]> {
+  execute(options?: ExecuteOptions): Promise<NarouRankingResult[]> {
     const date = formatDate(this.date$);
     this.set({ rtype: `${date}-${this.type$}` });
-    return this.api.executeRanking(this.params as RankingParams);
+    return this.api.executeRanking(this.params as RankingParams, options);
   }
 
   /**
    * ランキングAPIを実行し、取得したNコードを元になろう小説APIで詳細情報を取得して結合します。
    */
-  async executeWithFields(): Promise<
-    RankingResult<DefaultSearchResultFields>[]
-  >;
+  async executeWithFields(
+    fields?: never[] | undefined,
+    opt?: never[] | undefined,
+    options?: ExecuteOptions
+  ): Promise<RankingResult<DefaultSearchResultFields>[]>;
   /**
    * ランキングAPIを実行し、取得したNコードを元になろう小説APIで詳細情報を取得して結合します。
    *
@@ -131,7 +135,9 @@ export default class RankingBuilder {
    * @returns {Promise<RankingResult<SearchResultFields<TFields>>[]>} 詳細情報を含むランキング結果の配列
    */
   async executeWithFields<TFields extends Fields>(
-    fields: TFields | TFields[]
+    fields: TFields | TFields[],
+    opt?: never | never[],
+    options?: ExecuteOptions
   ): Promise<RankingResult<SearchResultFields<TFields>>[]>;
   /**
    * ランキングAPIを実行し、取得したNコードを元になろう小説APIで詳細情報を取得して結合します。
@@ -141,7 +147,8 @@ export default class RankingBuilder {
    */
   async executeWithFields(
     fields: never[],
-    opt: OptionalFields | OptionalFields[]
+    opt: OptionalFields | OptionalFields[],
+    options?: ExecuteOptions
   ): Promise<RankingResult<DefaultSearchResultFields | "weekly_unique">[]>;
   /**
    * ランキングAPIを実行し、取得したNコードを元になろう小説APIで詳細情報を取得して結合します。
@@ -153,7 +160,8 @@ export default class RankingBuilder {
    */
   async executeWithFields<TFields extends Fields>(
     fields: TFields | TFields[],
-    opt: OptionalFields | OptionalFields[]
+    opt: OptionalFields | OptionalFields[],
+    options?: ExecuteOptions
   ): Promise<RankingResult<SearchResultFields<TFields> | "weekly_unique">[]>;
   /**
    * ランキングAPIを実行し、取得したNコードを元になろう小説APIで詳細情報を取得して結合します。
@@ -169,9 +177,10 @@ export default class RankingBuilder {
     TOpt extends OptionalFields | undefined = undefined
   >(
     fields: TFields | TFields[] = [],
-    opt?: TOpt
+    opt?: TOpt,
+    options?: ExecuteOptions
   ): Promise<RankingResult<SearchResultFields<TFields>>[]> {
-    const ranking = await this.execute();
+    const ranking = await this.execute(options);
     const fields$ = Array.isArray(fields)
       ? fields.length == 0
         ? []
@@ -186,7 +195,7 @@ export default class RankingBuilder {
     }
     builder.ncode(rankingNcodes);
     builder.limit(ranking.length);
-    const result = await builder.execute();
+    const result = await builder.execute(options);
 
     return ranking.map<
       RankingResult<
diff --git a/src/search-builder-r18.ts b/src/search-builder-r18.ts
index 02e961c..498b43a 100644
--- a/src/search-builder-r18.ts
+++ b/src/search-builder-r18.ts
@@ -1,4 +1,5 @@
 import { NovelSearchBuilderBase } from "./search-builder.js";
+import type { ExecuteOptions } from "./narou.js";
 import type NarouSearchResults from "./narou-search-results.js";
 import type {
   NarouSearchResult,
@@ -28,10 +29,13 @@ export default class SearchBuilderR18<
   /**
    * なろう小説APIへの検索リクエストを実行する
    * @override
+   * @param options 実行オプション
    * @returns {Promise<NarouSearchResults>} 検索結果
    */
-  execute(): Promise<NarouSearchResults<NarouSearchResult, T | TOpt>> {
-    return this.api.executeNovel18(this.params);
+  execute(
+    options?: ExecuteOptions
+  ): Promise<NarouSearchResults<NarouSearchResult, T | TOpt>> {
+    return this.api.executeNovel18(this.params, options);
   }
 
   /**
diff --git a/src/search-builder.ts b/src/search-builder.ts
index 30f871d..4e82a99 100644
--- a/src/search-builder.ts
+++ b/src/search-builder.ts
@@ -1,4 +1,5 @@
 import type NarouNovel from "./narou.js";
+import type { ExecuteOptions } from "./narou.js";
 import type {
   NarouSearchResult,
   SearchResultFields,
@@ -40,7 +41,7 @@ export abstract class SearchBuilderBase<
   constructor(
     protected params: TParams = {} as TParams,
     protected api: NarouNovel
-  ) {}
+  ) { }
 
   /**
    * 配列から重複を除去する
@@ -472,10 +473,13 @@ export abstract class NovelSearchBuilderBase<
 
   /**
    * なろう小説APIへの検索リクエストを実行する
+   * @param options 実行オプション
    * @returns {Promise<NarouSearchResults>} 検索結果
    */
-  execute(): Promise<NarouSearchResults<NarouSearchResult, T>> {
-    return this.api.executeNovel(this.params);
+  execute(
+    options?: ExecuteOptions
+  ): Promise<NarouSearchResults<NarouSearchResult, T>> {
+    return this.api.executeNovel(this.params, options);
   }
 }
 
diff --git a/src/user-search.ts b/src/user-search.ts
index eb607d9..09c1fe5 100644
--- a/src/user-search.ts
+++ b/src/user-search.ts
@@ -5,6 +5,7 @@ import type {
 } from "./narou-search-results.js";
 import type { UserFields, UserOrder, UserSearchParams } from "./params.js";
 import { SearchBuilderBase } from "./search-builder.js";
+import type { ExecuteOptions } from "./narou.js";
 
 /**
  * なろうユーザ検索API
@@ -102,9 +103,15 @@ export default class UserSearchBuilder<
 
   /**
    * なろう小説APIへのリクエストを実行する
+   * @param options 実行オプション
    * @returns ランキング
    */
-  execute(): Promise<NarouSearchResults<UserSearchResult, TField>> {
-    return this.api.executeUserSearch(this.params as UserSearchParams);
+  execute(
+    options?: ExecuteOptions
+  ): Promise<NarouSearchResults<UserSearchResult, TField>> {
+    return this.api.executeUserSearch(
+      this.params as UserSearchParams,
+      options
+    );
   }
 }
diff --git a/test/narou-fetch.test.ts b/test/narou-fetch.test.ts
index f5578c4..6f85d17 100644
--- a/test/narou-fetch.test.ts
+++ b/test/narou-fetch.test.ts
@@ -166,4 +166,23 @@ describe('NarouNovelFetch', () => {
     // リクエストが呼ばれたことを確認
     expect(requestSpy).toHaveBeenCalled();
   });
+
+  it('should pass fetchOptions to fetch', async () => {
+    // MSWでエンドポイントをモック
+    server.use(
+      http.get('https://api.example.com', ({ request }) => {
+        expect(request.headers.get('user-agent')).toBe('node-narou');
+        return responseGzipOrJson(mockData, new URL(request.url));
+      })
+    );
+
+    const narouFetch = new NarouNovelFetch();
+
+    // @ts-expect-error - Accessing protected method for testing
+    await narouFetch.execute(
+      { gzip: 0 },
+      'https://api.example.com',
+      { fetchOptions: { headers: { 'user-agent': 'node-narou' } } }
+    );
+  });
 });
\ No newline at end of file
diff --git a/test/ranking-history.test.ts b/test/ranking-history.test.ts
index b8e4761..ace0db7 100644
--- a/test/ranking-history.test.ts
+++ b/test/ranking-history.test.ts
@@ -1,9 +1,19 @@
-import { describe, it, expect } from 'vitest';
+import { describe, it, expect, beforeAll, afterEach, afterAll, vi } from 'vitest';
 import { formatRankingHistory } from '../src/ranking-history.js';
+import NarouAPI from '../src';
 import { RankingType } from '../src/params.js';
 import { parse } from 'date-fns';
+import { setupServer } from 'msw/node';
+import { http } from 'msw';
+import { responseGzipOrJson } from './mock';
+
+const server = setupServer();
 
 describe('formatRankingHistory', () => {
+  beforeAll(() => server.listen());
+  afterEach(() => server.resetHandlers());
+  afterAll(() => server.close());
+
   it('should format raw ranking history data correctly', () => {
     const input = {
       rtype: '20230101-d',
@@ -71,4 +81,31 @@ describe('formatRankingHistory', () => {
       rank: 3
     });
   });
-});
\ No newline at end of file
+
+  it('should pass execute options to ranking history request', async () => {
+    const mockFn = vi.fn();
+
+    server.use(
+      http.get('https://api.syosetu.com/rank/rankin/', ({ request }) => {
+        const url = new URL(request.url);
+        mockFn(request.headers.get('x-test'));
+        const response = [{ rtype: '20230101-d', pt: 100, rank: 5 }];
+        return responseGzipOrJson(response, url);
+      })
+    );
+
+    const result = await NarouAPI.rankingHistory('n0000a', {
+      fetchOptions: { headers: { 'x-test': 'hello' } }
+    });
+
+    expect(result).toHaveLength(1);
+    expect(result[0]).toEqual({
+      type: 'd' as RankingType,
+      date: parse('20230101', 'yyyyMMdd', new Date()),
+      pt: 100,
+      rank: 5
+    });
+    expect(mockFn).toHaveBeenCalledTimes(1);
+    expect(mockFn).toHaveBeenCalledWith('hello');
+  });
+});
diff --git a/test/ranking.test.ts b/test/ranking.test.ts
index 8febe23..46fbda5 100644
--- a/test/ranking.test.ts
+++ b/test/ranking.test.ts
@@ -15,6 +15,19 @@ import { responseGzipOrJson } from "./mock";
 
 const server = setupServer();
 
+const setupHeaderHandler = (mockFn: (...args: unknown[]) => void) => {
+  server.use(
+    http.get("https://api.syosetu.com/rank/rankget/", ({ request }) => {
+      const url = new URL(request.url);
+      mockFn(request.headers.get("x-test"));
+      const response: NarouRankingResult[] = [
+        { ncode: "N0001AA", rank: 1, pt: 1000 },
+      ];
+      return responseGzipOrJson(response, url);
+    })
+  );
+};
+
 describe("RankingBuilder", () => {
   beforeAll(() => {
     vi.useFakeTimers({
@@ -479,4 +492,71 @@ describe("RankingBuilder", () => {
       expect(result[0].title).toBe("タイトル");
     });
   });
+
+  describe("execute options", () => {
+    test("fetchOptionsがリクエストに渡される", async () => {
+      const mockFn = vi.fn();
+      setupHeaderHandler(mockFn);
+
+      const result = await ranking().execute({
+        fetchOptions: { headers: { "x-test": "hello" } },
+      });
+
+      expect(result).toHaveLength(1);
+      expect(result[0].ncode).toBe("N0001AA");
+      expect(result[0].rank).toBe(1);
+      expect(result[0].pt).toBe(1000);
+      expect(mockFn).toHaveBeenCalledTimes(1);
+      expect(mockFn).toHaveBeenCalledWith("hello");
+    });
+  });
+
+  describe("executeWithFields options", async () => {
+    test("fetchOptionsがリクエストに渡される", async () => {
+      const mockRankingHeader = vi.fn();
+      const mockNovelRequest = vi.fn();
+
+      server.use(
+        http.get("https://api.syosetu.com/rank/rankget/", ({ request }) => {
+          const url = new URL(request.url);
+          mockRankingHeader(request.headers.get("x-test"));
+          const response: NarouRankingResult[] = [
+            { ncode: "N0001AA", rank: 1, pt: 1000 },
+          ];
+          return responseGzipOrJson(response, url);
+        }),
+        http.get("https://api.syosetu.com/novelapi/api/", ({ request }) => {
+          const url = new URL(request.url);
+          mockRankingHeader(request.headers.get("x-test"));
+          mockNovelRequest(
+            request.headers.get("x-test"),
+            url.searchParams.get("of"),
+            url.searchParams.size
+          );
+          const response = [
+            { allcount: 1 },
+            { ncode: "N0001AA", title: "タイトル" },
+          ];
+          return responseGzipOrJson(response, url);
+        })
+      );
+
+      const result = await ranking().executeWithFields(undefined, undefined, {
+        fetchOptions: { headers: { "x-test": "hello" } },
+      });
+
+      expect(result).toHaveLength(1);
+      expect(result[0].ncode).toBe("N0001AA");
+      expect(result[0].title).toBe("タイトル");
+      expect(mockRankingHeader).toHaveBeenCalledTimes(2);
+      expect(mockRankingHeader).toHaveBeenNthCalledWith(1, "hello");
+      expect(mockRankingHeader).toHaveBeenNthCalledWith(2, "hello");
+      expect(mockNovelRequest).toHaveBeenCalledTimes(1);
+      expect(mockNovelRequest).toHaveBeenCalledWith(
+        "hello",
+        "",
+        5 // ncode, gzip, out, of, lim
+      );
+    });
+  });
 });
diff --git a/test/search-builder-r18.test.ts b/test/search-builder-r18.test.ts
index a933936..7d31821 100644
--- a/test/search-builder-r18.test.ts
+++ b/test/search-builder-r18.test.ts
@@ -36,6 +36,19 @@ const setupMockHandler = (
   );
 };
 
+const setupHeaderHandler = (mockFn: (...args: unknown[]) => void) => {
+  server.use(
+    http.get("https://api.syosetu.com/novel18api/api/", ({ request }) => {
+      const url = new URL(request.url);
+      const response = [{ allcount: 1 }, { ncode: "N1234AB" }];
+
+      mockFn(request.headers.get("x-test"));
+
+      return responseGzipOrJson(response, url);
+    })
+  );
+};
+
 describe("SearchBuilderR18", () => {
   beforeAll(() => server.listen());
   afterEach(() => server.resetHandlers());
@@ -99,6 +112,24 @@ describe("SearchBuilderR18", () => {
     });
   });
 
+  describe("execute options", () => {
+    test("fetchOptionsがリクエストに渡される", async () => {
+      const mockFn = vi.fn();
+      setupHeaderHandler(mockFn);
+
+      const result = await NarouAPI.searchR18().execute({
+        fetchOptions: { headers: { "x-test": "hello" } },
+      });
+
+      expect(result.allcount).toBe(1);
+      expect(result.length).toBe(1);
+      expect(result.values).toHaveLength(1);
+      expect(result.values[0].ncode).toBe("N1234AB");
+      expect(mockFn).toHaveBeenCalledTimes(1);
+      expect(mockFn).toHaveBeenCalledWith("hello");
+    });
+  });
+
   describe("xid", () => {
     test("default", async () => {
       const mockFn = vi.fn();
@@ -214,4 +245,4 @@ describe("SearchBuilderR18", () => {
       expect(mockFn).toHaveBeenCalledWith("weekly", "json", 3);
     });
   });
-});
\ No newline at end of file
+});
diff --git a/test/search-builder.test.ts b/test/search-builder.test.ts
index ca2b187..57a8deb 100644
--- a/test/search-builder.test.ts
+++ b/test/search-builder.test.ts
@@ -42,6 +42,19 @@ const setupMockHandler = (
   );
 };
 
+const setupHeaderHandler = (mockFn: (...args: unknown[]) => void) => {
+  server.use(
+    http.get("https://api.syosetu.com/novelapi/api/", ({ request }) => {
+      const url = new URL(request.url);
+      const response = [{ allcount: 1 }, { ncode: "N1234AB" }];
+
+      mockFn(request.headers.get("x-test"));
+
+      return responseGzipOrJson(response, url);
+    })
+  );
+};
+
 describe("SearchBuilder", () => {
   beforeAll(() => server.listen());
   afterEach(() => server.resetHandlers());
@@ -115,6 +128,24 @@ describe("SearchBuilder", () => {
     });
   });
 
+  describe("execute options", () => {
+    test("fetchOptionsがリクエストに渡される", async () => {
+      const mockFn = vi.fn();
+      setupHeaderHandler(mockFn);
+
+      const result = await NarouAPI.search().execute({
+        fetchOptions: { headers: { "x-test": "hello" } },
+      });
+
+      expect(result.allcount).toBe(1);
+      expect(result.length).toBe(1);
+      expect(result.values).toHaveLength(1);
+      expect(result.values[0].ncode).toBe("N1234AB");
+      expect(mockFn).toHaveBeenCalledTimes(1);
+      expect(mockFn).toHaveBeenCalledWith("hello");
+    });
+  });
+
   describe("start", () => {
     test("default", async () => {
       const mockFn = vi.fn();
diff --git a/test/user-search.test.ts b/test/user-search.test.ts
index 783a882..5a538d5 100644
--- a/test/user-search.test.ts
+++ b/test/user-search.test.ts
@@ -35,6 +35,19 @@ const setupMockHandler = (
   );
 };
 
+const setupHeaderHandler = (mockFn: (...args: unknown[]) => void) => {
+  server.use(
+    http.get("https://api.syosetu.com/userapi/api/", ({ request }) => {
+      const url = new URL(request.url);
+      const response = [{ allcount: 1 }, { userid: 1234, name: "テストユーザー" }];
+
+      mockFn(request.headers.get("x-test"));
+
+      return responseGzipOrJson(response, url);
+    })
+  );
+};
+
 describe("UserSearchBuilder", () => {
   beforeAll(() => server.listen());
   afterEach(() => server.resetHandlers());
@@ -80,6 +93,24 @@ describe("UserSearchBuilder", () => {
     });
   });
 
+  describe("execute options", () => {
+    test("fetchOptionsがリクエストに渡される", async () => {
+      const mockFn = vi.fn();
+      setupHeaderHandler(mockFn);
+
+      const result = await NarouAPI.searchUser().execute({
+        fetchOptions: { headers: { "x-test": "hello" } },
+      });
+
+      expect(result.allcount).toBe(1);
+      expect(result.length).toBe(1);
+      expect(result.values).toHaveLength(1);
+      expect(result.values[0].userid).toBe(1234);
+      expect(mockFn).toHaveBeenCalledTimes(1);
+      expect(mockFn).toHaveBeenCalledWith("hello");
+    });
+  });
+
   describe("limit", () => {
     test("default", async () => {
       const mockFn = vi.fn();
@@ -476,4 +507,4 @@ describe("UserSearchBuilder", () => {
       expect(mockFn).toHaveBeenCalledWith(`${UserFields.userid}-${UserFields.name}`, "5", "json", 3);
     });
   });
-});
\ No newline at end of file
+});