diff --git a/websocket-sharp/Net/HttpListener.cs b/websocket-sharp/Net/HttpListener.cs
index cf2870b2..b7de73f0 100644
--- a/websocket-sharp/Net/HttpListener.cs
+++ b/websocket-sharp/Net/HttpListener.cs
@@ -765,9 +765,6 @@ namespace WebSocketSharp.Net
     {
       CheckDisposed ();
 
-      if (_listening)
-        return;
-
       lock (_contextRegistrySync) {
         CheckDisposed ();