diff --git a/packages/backend/src/core/MfmService.ts b/packages/backend/src/core/MfmService.ts
index 2055ea7f37..2200aeecea 100644
--- a/packages/backend/src/core/MfmService.ts
+++ b/packages/backend/src/core/MfmService.ts
@@ -413,7 +413,9 @@ export class MfmService {
 				const a = doc.createElement('a');
 				const { username, host, acct } = node.props;
 				const remoteUserInfo = mentionedRemoteUsers.find(remoteUser => remoteUser.username === username && remoteUser.host === host);
-				a.setAttribute('href', remoteUserInfo ? (remoteUserInfo.url ? remoteUserInfo.url : remoteUserInfo.uri) : `${this.config.url}/${acct}`);
+				a.setAttribute('href', remoteUserInfo
+					? (remoteUserInfo.url ? remoteUserInfo.url : remoteUserInfo.uri)
+					: `${this.config.url}/${acct.endsWith(`@${this.config.url}`) ? acct.substring(0, acct.length - this.config.url.length - 1) : acct}`);
 				a.className = 'u-url mention';
 				a.textContent = acct;
 				return a;