diff --git a/websocket-sharp/Net/HttpListenerResponse.cs b/websocket-sharp/Net/HttpListenerResponse.cs
index 4bcb0300..8fe7adb5 100644
--- a/websocket-sharp/Net/HttpListenerResponse.cs
+++ b/websocket-sharp/Net/HttpListenerResponse.cs
@@ -683,14 +683,14 @@ namespace WebSocketSharp.Net
         );
       }
 
-      if (!_sendChunked) {
+      if (_sendChunked) {
+        headers.InternalSet ("Transfer-Encoding", "chunked", true);
+      }
+      else {
         headers.InternalSet (
           "Content-Length", _contentLength.ToString (prov), true
         );
       }
-      else {
-        headers.InternalSet ("Transfer-Encoding", "chunked", true);
-      }
 
       /*
        * Apache forces closing the connection for these status codes: