diff --git a/websocket-sharp/WebSocket.cs b/websocket-sharp/WebSocket.cs
index e1f3e58b..e63a5198 100644
--- a/websocket-sharp/WebSocket.cs
+++ b/websocket-sharp/WebSocket.cs
@@ -2718,6 +2718,9 @@ namespace WebSocketSharp
       if (file == null)
         throw new ArgumentNullException ("file");
 
+      if (!file.Exists)
+        throw new ArgumentException ("The file does not exist.", "file");
+
       FileStream stream;
       if (!file.TryOpenRead (out stream))
         throw new ArgumentException ("Cannot be opened to read.", "file");