diff --git a/package.json b/package.json
index f9b50e2b..9f6fd774 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@technote-space/github-action-test-helper",
-  "version": "0.7.7",
+  "version": "0.7.8",
   "description": "Test helper for GitHub Actions.",
   "keywords": [
     "github",
diff --git a/src/types.ts b/src/types.ts
index 6369cf4c..c3684747 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,3 +1,4 @@
 import {GitHub} from '@actions/github/lib/utils';
+import {RestEndpointMethods} from '@octokit/plugin-rest-endpoint-methods/dist-types/generated/method-types';
 
-export type Octokit = InstanceType<typeof GitHub>;
+export type Octokit = InstanceType<typeof GitHub> & RestEndpointMethods;
diff --git a/src/utils.ts b/src/utils.ts
index bef3f982..238fd8b4 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -176,4 +176,4 @@ export const testProperties = (object: any, checks: { [key: string]: any }): voi
   });
 };
 
-export const getOctokit = (token?: string): Octokit => getOctokitInstance(token ?? 'test-token');
+export const getOctokit = (token?: string): Octokit => getOctokitInstance(token ?? 'test-token') as Octokit;