diff --git a/src/GvimExt/gvimext.h b/src/GvimExt/gvimext.h
index 3ad797e..b6be3a7 100644
--- a/src/GvimExt/gvimext.h
+++ b/src/GvimExt/gvimext.h
@@ -130,7 +130,7 @@
 	    int idHWnd);
 
     STDMETHODIMP InvokeSingleGvim(HWND hParent,
-	    LPCSTR pszWorkingDir,
+	    LPCWSTR workingDir,
 	    LPCSTR pszCmd,
 	    LPCSTR pszParam,
 	    int iShowCmd,