diff --git a/flask_oauthlib/provider/oauth2.py b/flask_oauthlib/provider/oauth2.py
index 86dbf532..9e189b93 100644
--- a/flask_oauthlib/provider/oauth2.py
+++ b/flask_oauthlib/provider/oauth2.py
@@ -626,9 +626,6 @@ def authenticate_client(self, request, *args, **kwargs):
             log.debug('Authenticate client failed, secret not match.')
             return False
 
-        if client.client_type != 'confidential':
-            log.debug('Authenticate client failed, not confidential.')
-            return False
         log.debug('Authenticate client success.')
         return True