diff --git a/pkg/middlewares/headers/header.go b/pkg/middlewares/headers/header.go
index 2ef1a2dd2..0852008e3 100644
--- a/pkg/middlewares/headers/header.go
+++ b/pkg/middlewares/headers/header.go
@@ -106,7 +106,7 @@ func (s *Header) PostRequestModifyResponseHeaders(res *http.Response) error {
 	}
 
 	if varyHeader != "" {
-		varyHeader += ", "
+		varyHeader += ","
 	}
 	varyHeader += "Origin"