diff --git a/Rakefile b/Rakefile
index a49519e8..431088a6 100644
--- a/Rakefile
+++ b/Rakefile
@@ -6,6 +6,7 @@ require "rake/extensiontask"
 require "rake/testtask"
 
 spec = eval(File.read('bigdecimal.gemspec'))
+spec.require_paths.insert(0, *%w[stub])
 Rake::ExtensionTask.new('bigdecimal', spec) do |ext|
   ext.lib_dir = File.join(*['lib', ENV['FAT_DIR']].compact)
   ext.cross_compile = true
diff --git a/bigdecimal.gemspec b/bigdecimal.gemspec
index 2638645c..f5c5c956 100644
--- a/bigdecimal.gemspec
+++ b/bigdecimal.gemspec
@@ -19,7 +19,6 @@ Gem::Specification.new do |s|
     bigdecimal.gemspec
     ext/bigdecimal/bigdecimal.c
     ext/bigdecimal/bigdecimal.h
-    lib/bigdecimal.rb
     lib/bigdecimal/jacobian.rb
     lib/bigdecimal/ludcmp.rb
     lib/bigdecimal/math.rb
@@ -28,6 +27,7 @@ Gem::Specification.new do |s|
     sample/linear.rb
     sample/nlsolve.rb
     sample/pi.rb
+    stub/bigdecimal.rb
   ]
 
   s.required_ruby_version = Gem::Requirement.new(">= 2.3.0".freeze)
diff --git a/lib/bigdecimal.rb b/lib/bigdecimal.rb
deleted file mode 100644
index c9682deb..00000000
--- a/lib/bigdecimal.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-begin
-  require "#{RUBY_VERSION[/\d+\.\d+/]}/bigdecimal.so"
-rescue LoadError
-  require 'bigdecimal.so'
-end
diff --git a/stub/bigdecimal.rb b/stub/bigdecimal.rb
new file mode 100644
index 00000000..94b2ec5d
--- /dev/null
+++ b/stub/bigdecimal.rb
@@ -0,0 +1 @@
+require "#{RUBY_VERSION[/\d+\.\d+/]}/bigdecimal.so"