diff --git a/ChangeLog b/ChangeLog
index f9f0f71e96..f5a7560d78 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Aug 16 21:14:06 2007  WATANABE Hirofumi  <eban@ruby-lang.org>
+
+	* configure.in (BASERUBY): need AC_SUBST.  [ruby-dev:31438]
+
 Thu Aug 16 19:18:26 2007  Tanaka Akira  <akr@fsij.org>
 
 	* test/ruby/sentence.rb: Sentence class implemented
diff --git a/configure.in b/configure.in
index 653fda5953..79916af4b6 100644
--- a/configure.in
+++ b/configure.in
@@ -20,6 +20,7 @@ AC_ARG_WITH(baseruby,
 	])
 test "`$BASERUBY -e 'p 42' 2>/dev/null`" = 42 ||
     AC_MSG_ERROR([executable host ruby is required.  use --with-baseruby option.])
+AC_SUBST(BASERUBY)
 
 AC_DEFUN([RUBY_MINGW32],
 [case "$host_os" in