diff --git a/Doc/tools/prechm.py b/Doc/tools/prechm.py
index 0367bda6567..adbebc85b04 100644
--- a/Doc/tools/prechm.py
+++ b/Doc/tools/prechm.py
@@ -23,7 +23,7 @@ import getopt
import cgi
usage_mode = '''
-Usage: make_chm.py [-c] [-k] [-p] [-v 1.5[.x]] filename
+Usage: pre_chm.py [-c] [-k] [-p] [-v 1.5[.x]] filename
-c: does not build filename.hhc (Table of Contents)
-k: does not build filename.hhk (Index)
-p: does not build filename.hhp (Project File)
@@ -93,8 +93,8 @@ contents_header = '''\