diff --git a/lib/tracer.gemspec b/lib/tracer.gemspec
new file mode 100644
index 0000000000..aa5eb3badd
--- /dev/null
+++ b/lib/tracer.gemspec
@@ -0,0 +1,21 @@
+require_relative "tracer/version"
+
+Gem::Specification.new do |spec|
+  spec.name          = "tracer"
+  spec.version       = Tracer::VERSION
+  spec.authors       = ["Keiju ISHITSUKA"]
+  spec.email         = ["keiju@ruby-lang.org"]
+
+  spec.summary       = %q{Outputs a source level execution trace of a Ruby program.}
+  spec.description   = %q{Outputs a source level execution trace of a Ruby program.}
+  spec.homepage      = "https://github.com/ruby/tracer"
+  spec.license       = "BSD-2-Clause"
+
+  spec.files         = [".gitignore", ".travis.yml", "Gemfile", "LICENSE.txt", "README.md", "Rakefile", "bin/console", "bin/setup", "lib/tracer.rb", "lib/tracer/version.rb", "tracer.gemspec"]
+  spec.bindir        = "exe"
+  spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
+  spec.require_paths = ["lib"]
+
+  spec.add_development_dependency "bundler"
+  spec.add_development_dependency "rake"
+end
diff --git a/lib/tracer/version.rb b/lib/tracer/version.rb
new file mode 100644
index 0000000000..f1b6dcd094
--- /dev/null
+++ b/lib/tracer/version.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Tracer
+  VERSION = "0.1.0"
+end