diff --git a/src/repository/github.ts b/src/repository/github.ts
index 10a8ab7..cd6d54e 100644
--- a/src/repository/github.ts
+++ b/src/repository/github.ts
@@ -2,7 +2,7 @@ import axios from "axios";
 import * as core from "@actions/core";
 
 type GithubGetPR = {
-  users: GithubGetReviewerNameResult[];
+  requested_reviewers: GithubGetReviewerNameResult[];
   title: string;
   html_url: string;
 };
@@ -23,5 +23,7 @@ export const getPR = async (
       headers: { authorization: `Bearer ${repoToken}` },
     },
   );
+  if (result.data.requested_reviewers.length == 0) return null;
+
   return result.data;
 };
diff --git a/src/usecase.ts b/src/usecase.ts
index cb685f8..e87a17f 100644
--- a/src/usecase.ts
+++ b/src/usecase.ts
@@ -43,7 +43,7 @@ export const execPrReviewRequestedMention = async (
     throw new Error("Can not find review requested user.");
   }
 
-  const reviewers = pr.users.map((user) => user.login)
+  const reviewers = pr.requested_reviewers.map((user) => user.login)
   core.info(`reviewers ${reviewers}`);
 
   const slackIds = convertToChatworkUsername(reviewers, mapping);