diff --git a/websocket-sharp/Net/WebHeaderCollection.cs b/websocket-sharp/Net/WebHeaderCollection.cs
index 6a21b23d..89ae2ac6 100644
--- a/websocket-sharp/Net/WebHeaderCollection.cs
+++ b/websocket-sharp/Net/WebHeaderCollection.cs
@@ -1638,7 +1638,9 @@ namespace WebSocketSharp.Net
       var key = header.ToString ();
       var name = getHeaderName (key);
 
-      doWithCheckingState (removeWithoutCheckingName, name, null, true, false);
+      checkRestricted (name, true);
+      checkAllowed (true);
+      base.Remove (name);
     }
 
     /// <summary>