diff --git a/lib/shellwords.rb b/lib/shellwords.rb
index 4368a53..5866601 100644
--- a/lib/shellwords.rb
+++ b/lib/shellwords.rb
@@ -68,6 +68,9 @@
 # 1: {IEEE Std 1003.1-2008, 2016 Edition, the Shell & Utilities volume}[http://pubs.opengroup.org/onlinepubs/9699919799/utilities/contents.html]
 
 module Shellwords
+
+  VERSION = "0.1.0"
+
   # Splits a string into an array of tokens in the same way the UNIX
   # Bourne shell does.
   #
diff --git a/shellwords.gemspec b/shellwords.gemspec
index 8ae87b2..d60ab5f 100644
--- a/shellwords.gemspec
+++ b/shellwords.gemspec
@@ -1,6 +1,14 @@
+name = File.basename(__FILE__, ".gemspec")
+version = ["lib", Array.new(name.count("-")+1).join("/")].find do |dir|
+  break File.foreach(File.join(__dir__, dir, "#{name.tr('-', '/')}.rb")) do |line|
+    /^\s*VERSION\s*=\s*"(.*)"/ =~ line and break $1
+  end rescue nil
+end
+
+
 Gem::Specification.new do |spec|
-  spec.name          = "shellwords"
-  spec.version       = "0.1.0"
+  spec.name          = name
+  spec.version       = version
   spec.authors       = ["Akinori MUSHA"]
   spec.email         = ["knu@idaemons.org"]