diff --git a/websocket-sharp/Ext.cs b/websocket-sharp/Ext.cs
index 57b43193..198e6af3 100644
--- a/websocket-sharp/Ext.cs
+++ b/websocket-sharp/Ext.cs
@@ -201,6 +201,13 @@ namespace WebSocketSharp
       }
     }
 
+    internal static string CheckIfCanAccept (this WebSocketState state)
+    {
+      return state != WebSocketState.Connecting
+             ? "This operation has already been done."
+             : null;
+    }
+
     internal static string CheckIfCanRead (this Stream stream)
     {
       return stream == null
diff --git a/websocket-sharp/WebSocket.cs b/websocket-sharp/WebSocket.cs
index 76b69990..551d4749 100644
--- a/websocket-sharp/WebSocket.cs
+++ b/websocket-sharp/WebSocket.cs
@@ -592,6 +592,32 @@ namespace WebSocketSharp
 
     #region Private Methods
 
+    // As server
+    private bool accept ()
+    {
+      lock (_forConn) {
+        var msg = _readyState.CheckIfCanAccept ();
+        if (msg != null) {
+          _logger.Error (msg);
+          error ("An error has occurred in accepting.", null);
+
+          return false;
+        }
+
+        try {
+          if (acceptHandshake ()) {
+            _readyState = WebSocketState.Open;
+            return true;
+          }
+        }
+        catch (Exception ex) {
+          processException (ex, "An exception has occurred while accepting.");
+        }
+
+        return false;
+      }
+    }
+
     // As server
     private bool acceptHandshake ()
     {