diff --git a/Rakefile b/Rakefile
index dd14c8b02..2f6fa056f 100644
--- a/Rakefile
+++ b/Rakefile
@@ -5,10 +5,12 @@ MRUBY_ROOT = File.dirname(File.expand_path(__FILE__))
 MRUBY_BUILD_HOST_IS_CYGWIN = RUBY_PLATFORM.include?('cygwin')
 MRUBY_BUILD_HOST_IS_OPENBSD = RUBY_PLATFORM.include?('openbsd')
 
+$LOAD_PATH << File.join(MRUBY_ROOT, "lib")
+
 # load build systems
-load "#{MRUBY_ROOT}/tasks/ruby_ext.rake"
-load "#{MRUBY_ROOT}/tasks/mruby_build.rake"
-load "#{MRUBY_ROOT}/tasks/mrbgem_spec.rake"
+require "mruby-core-ext"
+require "mruby/build"
+require "mruby/gem"
 
 # load configuration file
 MRUBY_CONFIG = (ENV['MRUBY_CONFIG'] && ENV['MRUBY_CONFIG'] != '') ? ENV['MRUBY_CONFIG'] : "#{MRUBY_ROOT}/build_config.rb"
diff --git a/tasks/ruby_ext.rake b/lib/mruby-core-ext.rb
similarity index 100%
rename from tasks/ruby_ext.rake
rename to lib/mruby-core-ext.rb
diff --git a/tasks/mruby_build.rake b/lib/mruby/build.rb
similarity index 98%
rename from tasks/mruby_build.rake
rename to lib/mruby/build.rb
index f5d4374d1..7d6aa49e1 100644
--- a/tasks/mruby_build.rake
+++ b/lib/mruby/build.rb
@@ -1,5 +1,5 @@
-load "#{MRUBY_ROOT}/tasks/mruby_build_gem.rake"
-load "#{MRUBY_ROOT}/tasks/mruby_build_commands.rake"
+require "mruby/build/load_gems"
+require "mruby/build/command"
 
 module MRuby
   class << self
@@ -241,7 +241,7 @@ EOS
         else
           compiler.defines += %w(DISABLE_GEMS)
         end
-        compiler.define_rules build_dir, File.expand_path(File.join(File.dirname(__FILE__), '..'))
+        compiler.define_rules build_dir, File.expand_path(File.join(File.dirname(__FILE__), '..', '..'))
       end
     end
 
diff --git a/tasks/mruby_build_commands.rake b/lib/mruby/build/command.rb
similarity index 100%
rename from tasks/mruby_build_commands.rake
rename to lib/mruby/build/command.rb
diff --git a/tasks/mruby_build_gem.rake b/lib/mruby/build/load_gems.rb
similarity index 100%
rename from tasks/mruby_build_gem.rake
rename to lib/mruby/build/load_gems.rb
diff --git a/tasks/mrbgem_spec.rake b/lib/mruby/gem.rb
similarity index 100%
rename from tasks/mrbgem_spec.rake
rename to lib/mruby/gem.rb