diff --git a/websocket-sharp/WebSocket.cs b/websocket-sharp/WebSocket.cs
index f6585243..10c3d795 100644
--- a/websocket-sharp/WebSocket.cs
+++ b/websocket-sharp/WebSocket.cs
@@ -615,12 +615,12 @@ namespace WebSocketSharp
           Uri uri;
           if (!Uri.TryCreate (value, UriKind.Absolute, out uri)) {
             msg = "Not an absolute URI string.";
-            throw new ArgumentException (msg, value);
+            throw new ArgumentException (msg, "value");
           }
 
           if (uri.Segments.Length > 1) {
             msg = "It includes the path segments.";
-            throw new ArgumentException (msg, value);
+            throw new ArgumentException (msg, "value");
           }
         }