diff --git a/ChangeLog b/ChangeLog
index 528bf38d65..ad58314074 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Jul 10 14:41:34 2009  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* marshal.c (r_object0): set encoding only if the encoding
+	  is not US-ASCII.
+
 Fri Jul 10 11:41:39 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* include/ruby/ruby.h (rb_obj_{untrust,untrusted,trust}): added
diff --git a/marshal.c b/marshal.c
index cbed195b5b..860b23f11b 100644
--- a/marshal.c
+++ b/marshal.c
@@ -1376,7 +1376,8 @@ r_object0(struct load_arg *arg, int *ivp, VALUE extmod)
 		r_ivar(v, arg);
 		*ivp = Qfalse;
 	    }
-	    rb_enc_copy(str, v);
+	    if (rb_enc_get_index(v) != rb_usascii_encindex())
+		rb_enc_copy(str, v);
 	    if (rb_enc_get_index(str) != rb_utf8_encindex()) {
 #define f_gsub_bang(x,y,z) rb_funcall(x, rb_intern("gsub!"), 2, y, z)
 		f_gsub_bang(str, rb_reg_new("\\\\u", 3, 0), rb_usascii_str_new_cstr("u"));
diff --git a/version.h b/version.h
index 5463ce5543..5a73ec9fdb 100644
--- a/version.h
+++ b/version.h
@@ -4,7 +4,7 @@
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 9
 #define RUBY_VERSION_TEENY 1
-#define RUBY_PATCHLEVEL 228
+#define RUBY_PATCHLEVEL 229
 #define RUBY_RELEASE_YEAR 2009
 #define RUBY_RELEASE_MONTH 7
 #define RUBY_RELEASE_DAY 12