diff --git a/ChangeLog b/ChangeLog
index 1db9daa38c..87119c9381 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Aug 21 15:01:35 2009  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* ext/readline/readline.c (readline_readline): use rb_prep_terminal
+	  only on Windows.
+
 Fri Aug 21 07:25:45 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/rdoc/ri/gemdirs.rb: split from lib/rdoc/ri/paths.rb to ge
diff --git a/ext/readline/readline.c b/ext/readline/readline.c
index 25b8013177..abb9a0a33a 100644
--- a/ext/readline/readline.c
+++ b/ext/readline/readline.c
@@ -144,7 +144,6 @@ readline_event(void)
 static VALUE
 readline_get(VALUE prompt)
 {
-    rl_prep_terminal(1);
     return (VALUE)readline((char *)prompt);
 }
 
@@ -250,6 +249,9 @@ readline_readline(int argc, VALUE *argv, VALUE self)
 
     if (!isatty(0) && errno == EBADF) rb_raise(rb_eIOError, "closed stdin");
 
+#ifdef _WIN32
+    rl_prep_terminal(1);
+#endif
     buff = (char*)rb_protect(readline_get, (VALUE)prompt, &status);
     if (status) {
 #if defined HAVE_RL_CLEANUP_AFTER_SIGNAL