diff --git a/Rakefile b/Rakefile
index 2a8e11d43..ef7d536c6 100644
--- a/Rakefile
+++ b/Rakefile
@@ -31,6 +31,7 @@ load "#{MRUBY_ROOT}/tasks/presym.rake"
 load "#{MRUBY_ROOT}/tasks/test.rake"
 load "#{MRUBY_ROOT}/tasks/benchmark.rake"
 load "#{MRUBY_ROOT}/tasks/doc.rake"
+load "#{MRUBY_ROOT}/tasks/install.rake"
 
 ##############################
 # generic build targets, rules
@@ -67,34 +68,6 @@ task :deep_clean => %w[clean doc:clean] do
   puts "Cleaned up mrbgems build folder"
 end
 
-PREFIX = ENV['PREFIX'] || ENV['INSTALL_PREFIX'] || '/usr/local'
-
-desc "install compiled products"
-task :install => :install_bin do
-  if host = MRuby.targets['host']
-    install_D host.libmruby_static, File.join(PREFIX, "lib", File.basename(host.libmruby_static))
-    # install mruby.h and mrbconf.h
-    Dir.glob(File.join(MRUBY_ROOT, "include", "*.h")) do |src|
-      install_D src, File.join(PREFIX, "include", File.basename(src))
-    end
-    Dir.glob(File.join(MRUBY_ROOT, "include", "mruby", "*.h")) do |src|
-      install_D src, File.join(PREFIX, "include", "mruby", File.basename(src))
-    end
-    Dir.glob(File.join(File.join(MRUBY_ROOT, "build", "host", "include", "mruby", "presym", "*.h"))) do |src|
-      install_D src, File.join(PREFIX, "include", "mruby", "presym", File.basename(src))
-    end
-  end
-end
-
-desc "install compiled executable (on host)"
-task :install_bin => :all do
-  if host = MRuby.targets['host']
-    Dir.glob(File.join(MRUBY_ROOT, "bin", "*")) do |src|
-      install_D src, File.join(PREFIX, "bin", File.basename(src))
-    end
-  end
-end
-
 desc "run all pre-commit hooks against all files"
 task :check do
   sh "pre-commit run --all-files"
diff --git a/lib/mruby/build.rb b/lib/mruby/build.rb
index 4925cee33..e6298d71f 100644
--- a/lib/mruby/build.rb
+++ b/lib/mruby/build.rb
@@ -7,6 +7,8 @@ module MRuby
   autoload :Lockfile, "mruby/lockfile"
   autoload :Presym, "mruby/presym"
 
+  INSTALL_PREFIX = ENV['PREFIX'] || ENV['INSTALL_PREFIX'] || '/usr/local'
+
   class << self
     def targets
       @targets ||= {}
diff --git a/tasks/install.rake b/tasks/install.rake
new file mode 100644
index 000000000..c83d30a4e
--- /dev/null
+++ b/tasks/install.rake
@@ -0,0 +1,25 @@
+desc "install compiled products"
+task :install => :install_bin do
+  if host = MRuby.targets['host']
+    install_D host.libmruby_static, File.join(MRuby::INSTALL_PREFIX, "lib", File.basename(host.libmruby_static))
+    # install mruby.h and mrbconf.h
+    Dir.glob(File.join(MRUBY_ROOT, "include", "*.h")) do |src|
+      install_D src, File.join(MRuby::INSTALL_PREFIX, "include", File.basename(src))
+    end
+    Dir.glob(File.join(MRUBY_ROOT, "include", "mruby", "*.h")) do |src|
+      install_D src, File.join(MRuby::INSTALL_PREFIX, "include", "mruby", File.basename(src))
+    end
+    Dir.glob(File.join(File.join(MRUBY_ROOT, "build", "host", "include", "mruby", "presym", "*.h"))) do |src|
+      install_D src, File.join(MRuby::INSTALL_PREFIX, "include", "mruby", "presym", File.basename(src))
+    end
+  end
+end
+
+desc "install compiled executable (on host)"
+task :install_bin => :all do
+  if host = MRuby.targets['host']
+    Dir.glob(File.join(MRUBY_ROOT, "bin", "*")) do |src|
+      install_D src, File.join(MRuby::INSTALL_PREFIX, "bin", File.basename(src))
+    end
+  end
+end