diff --git a/src/modules/core/index.ts b/src/modules/core/index.ts
index cb319dc..697b88b 100644
--- a/src/modules/core/index.ts
+++ b/src/modules/core/index.ts
@@ -26,6 +26,11 @@ export default class CoreModule implements IModule {
 
 			const name = msg.text.match(/^(.+?)って呼んで/)[1];
 
+			if (name.length > 10) {
+				msg.reply(serifs.core.tooLong);
+				return true;
+			}
+
 			const withSan =
 				name.endsWith('さん') ||
 				name.endsWith('くん') ||
diff --git a/src/serifs.ts b/src/serifs.ts
index 24da184..83053ad 100644
--- a/src/serifs.ts
+++ b/src/serifs.ts
@@ -7,6 +7,7 @@ export default {
 		goodMorningWithName: 'おはようございます、{name}！',
 		goodNight: 'おやすみなさい！',
 		goodNightWithName: 'おやすみなさい、{name}！',
+		tooLong: '長すぎる気がします...'
 	},
 
 	/**