diff --git a/ChangeLog b/ChangeLog
index 60b47c6485..dbd25ec42f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,6 @@
 Sat Jul 14 16:11:24 2007  Tanaka Akira  <akr@fsij.org>
 
-	* configure.in: add --enable-valgrind.
+	* configure.in: add --with-valgrind.
 
 	* gc.h (SET_MACHINE_STACK_END): new macro to replace
 	  rb_gc_set_stack_end.  it find out accurate stack boundary by
@@ -12,7 +12,7 @@ Sat Jul 14 16:11:24 2007  Tanaka Akira  <akr@fsij.org>
 	* gc.c (mark_current_thread): extracted from garbage_collect.
 	  it use SET_MACHINE_STACK_END to not scan out of stack area.
 	  it notify conservative GC information to valgrind if
-	  --enable-valgrind.
+	  --with-valgrind.
 
 Sat Jul 14 14:04:06 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
diff --git a/configure.in b/configure.in
index 95daff2379..dcccf18892 100644
--- a/configure.in
+++ b/configure.in
@@ -873,8 +873,8 @@ fi
 
 AC_CHECK_FUNCS(backtrace)
 
-AC_ARG_ENABLE(valgrind,
-        [  --enable-valgrind       enable valgrind memcheck support.],
+AC_ARG_WITH(valgrind,
+        [  --with-valgrind         enable valgrind memcheck support.],
         [AC_CHECK_HEADERS(valgrind/memcheck.h)])
 
 dnl default value for $KANJI