diff --git a/lib/execjs/pcruntime/context_process_runtime.rb b/lib/execjs/pcruntime/context_process_runtime.rb
index 1acf8c3..00a7efb 100644
--- a/lib/execjs/pcruntime/context_process_runtime.rb
+++ b/lib/execjs/pcruntime/context_process_runtime.rb
@@ -5,6 +5,7 @@
 require 'json'
 require 'net/protocol'
 require 'net/http'
+require 'shellwords'
 
 module ExecJS
   module PCRuntime