diff --git a/test/drb/drbtest.rb b/test/drb/drbtest.rb
index 4488e1be21..40ef35ef2e 100644
--- a/test/drb/drbtest.rb
+++ b/test/drb/drbtest.rb
@@ -3,17 +3,16 @@ require 'test/unit'
 require 'drb/drb'
 require 'drb/extservm'
 require 'timeout'
-require 'shellwords'
 
 module DRbTests
 
 class DRbService
   @@manager = DRb::ExtServManager.new
-  @@ruby = Shellwords.escape(EnvUtil.rubybin)
-  @@ruby += " -d" if $DEBUG
+  @@ruby = [EnvUtil.rubybin]
+  @@ruby << "-d" if $DEBUG
   def self.add_service_command(nm)
     dir = File.dirname(File.expand_path(__FILE__))
-    DRb::ExtServManager.command[nm] = [@@ruby, "#{dir}/#{nm}"]
+    DRb::ExtServManager.command[nm] = @@ruby + ["#{dir}/#{nm}"]
   end
 
   %w(ut_drb.rb ut_array.rb ut_port.rb ut_large.rb ut_safe1.rb ut_eval.rb ut_eq.rb).each do |nm|