diff --git a/src/api/service/github.ts b/src/api/service/github.ts
index 25f0c9d9a..e1a465894 100644
--- a/src/api/service/github.ts
+++ b/src/api/service/github.ts
@@ -34,6 +34,7 @@ module.exports = async (app: express.Application) => {
 			case 'opened': title = 'Issueが立ちました'; break;
 			case 'closed': title = 'Issueが閉じられました'; break;
 			case 'reopened': title = 'Issueが開きました'; break;
+			default: return;
 		}
 		const text = `${title}: ${event.payload.issue.number}「${event.payload.issue.title}」\n${event.payload.issue.html_url}`;
 		post(text);