diff --git a/ChangeLog b/ChangeLog
index 77aeaf4aee..c13686d912 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Mar 20 19:44:09 2002  Tanaka Akira  <akr@m17n.org>
+
+	* mkconfig.rb: don't touch rbconfig.rb if there is a trouble.
+
 Wed Mar 20 16:05:37 2002  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* eval.c (is_defined): should check receiver only once.
diff --git a/mkconfig.rb b/mkconfig.rb
index 5eb0b18d1c..d558583b61 100644
--- a/mkconfig.rb
+++ b/mkconfig.rb
@@ -7,7 +7,8 @@ srcdir = $srcdir if $srcdir
 File.makedirs(File.dirname(rbconfig_rb), true)
 
 version = RUBY_VERSION
-config = open(rbconfig_rb, "w")
+rbconfig_rb_tmp = rbconfig_rb + '.tmp'
+config = open(rbconfig_rb_tmp, "w")
 $stdout.reopen(config)
 
 fast = {'prefix'=>TRUE, 'ruby_install_name'=>TRUE, 'INSTALL'=>TRUE, 'EXEEXT'=>TRUE}
@@ -111,5 +112,6 @@ print <<EOS
 end
 EOS
 config.close
+File.rename(rbconfig_rb_tmp, rbconfig_rb)
 
 # vi:set sw=2: