diff --git a/ChangeLog b/ChangeLog
index 3b76bc9394..f95f8d340d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon Apr 16 18:22:14 2012  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* spec/default.mspec: expand relative path for ruby_exe which uses
+	  them with Dir.chdir; it breaks relative paths, for example
+	  core/kernel/exec_spec.rb.
+
 Mon Apr 16 16:22:40 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* win32/win32.c (gmtime_r, localtime_r): POSIX compliant reentrant
diff --git a/spec/default.mspec b/spec/default.mspec
index a23df2f25a..c4b75f614a 100644
--- a/spec/default.mspec
+++ b/spec/default.mspec
@@ -13,9 +13,9 @@ class MSpecScript
   set :target, File.join(builddir, "miniruby#{config['exeext']}")
   set :prefix, File.expand_path('rubyspec', File.dirname(__FILE__))
   set :flags, %W[
-    -I#{srcdir}/lib
-    -I#{srcdir}/#{config['EXTOUT']}/common
-    -I#{srcdir}/-
-    #{srcdir}/tool/runruby.rb --extout=#{config['EXTOUT']}
+    -I#{File.expand_path srcdir}/lib
+    -I#{File.expand_path srcdir}/#{config['EXTOUT']}/common
+    -I#{File.expand_path srcdir}/-
+    #{File.expand_path srcdir}/tool/runruby.rb --archdir=#{Dir.pwd} --extout=#{config['EXTOUT']}
   ]
 end