diff --git a/lib/open-uri.rb b/lib/open-uri.rb
index 93e8cfc..0052bb4 100644
--- a/lib/open-uri.rb
+++ b/lib/open-uri.rb
@@ -89,6 +89,9 @@ def self.open(name, *rest, &block)
 # Author:: Tanaka Akira <akr@m17n.org>
 
 module OpenURI
+
+  VERSION = "0.3.0"
+
   Options = {
     :proxy => true,
     :proxy_http_basic_authentication => true,
diff --git a/open-uri.gemspec b/open-uri.gemspec
index cad63e4..b6aaf35 100644
--- a/open-uri.gemspec
+++ b/open-uri.gemspec
@@ -1,6 +1,13 @@
+name = File.basename(__FILE__, ".gemspec")
+version = ["lib", "."].find do |dir|
+  break File.foreach(File.join(__dir__, dir, "#{name}.rb")) do |line|
+    /^\s*VERSION\s*=\s*"(.*)"/ =~ line and break $1
+  end rescue nil
+end
+
 Gem::Specification.new do |spec|
-  spec.name          = "open-uri"
-  spec.version       = "0.3.0"
+  spec.name          = name
+  spec.version       = version
   spec.authors       = ["Tanaka Akira"]
   spec.email         = ["akr@fsij.org"]