diff --git a/.circleci/config.yml b/.circleci/config.yml
index a7ff947..a81f3ab 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -32,27 +32,37 @@ jobs:
       - unity_activate:
           unity_version: << parameters.unity_version >>
           unity_license: << parameters.unity_license >>
-      # - run:
-      #     name: Build Linux(Mono)
-      #     command: /opt/Unity/Editor/Unity -quit -batchmode -nographics -silent-crashes -logFile -projectPath . -executeMethod UnitTestBuilder.BuildUnitTest /headless /ScriptBackend Mono2x /BuildTarget StandaloneLinux64
-      #     working_directory: src/RandomFixtureKit.Unity
-      # - run: src/RandomFixtureKit.Unity/bin/UnitTest/StandaloneLinux64_Mono2x/test
-  # build-and-create-package:
-  #   executor: unity
-  #   steps:
-  #     - checkout
-  #     - unity_activate
-  #     - run:
-  #         name: Export unitypackage
-  #         command: /opt/Unity/Editor/Unity -quit -batchmode -nographics -silent-crashes -logFile -projectPath . -executeMethod PackageExporter.Export
-  #         working_directory: src/MagicOnion.Client.Unity
-  #     - store_artifacts:
-  #         path: src/MagicOnion.Client.Unity/MagicOnion.Client.Unity.unitypackage
-  #         destination: /MagicOnion.Client.Unity.unitypackage
+      - run:
+          name: Build Linux(Mono)
+          command: /opt/Unity/Editor/Unity -quit -batchmode -nographics -silent-crashes -logFile -projectPath . -executeMethod UnitTestBuilder.BuildUnitTest /headless /ScriptBackend Mono2x /BuildTarget StandaloneLinux64
+          working_directory: .
+      - run: ./bin/UnitTest/StandaloneLinux64_Mono2x/test
+  build-and-create-package:
+    parameters:
+      unity_version: {type: string}
+      unity_license: {type: string}
+    executor:
+      name: unity
+      version: << parameters.unity_version >>
+    steps:
+      - checkout
+      - unity_activate:
+          unity_version: << parameters.unity_version >>
+          unity_license: << parameters.unity_license >>
+      - run:
+          name: Export unitypackage
+          command: /opt/Unity/Editor/Unity -quit -batchmode -nographics -silent-crashes -logFile -projectPath . -executeMethod PackageExporter.Export
+          working_directory: .
+     - store_artifacts:
+          path: ./UniRx.Async.unitypackage
+          destination: /UniRx.Async.unitypackage
 workflows:
   version: 2
   build-unity:
     jobs:
+      - build-and-create-package:
+          unity_version: 2019.3.0a2
+          unity_license: ${UNITY_LICENSE_2019_3}
       - build-and-test:
           unity_version: 2019.3.0a2
           unity_license: ${UNITY_LICENSE_2019_3}
diff --git a/.gitignore b/.gitignore
index 174b65e..29f4b76 100644
--- a/.gitignore
+++ b/.gitignore
@@ -141,3 +141,7 @@ UniRx\.Async\.Tests\.csproj
 UniTask\.sln
 
 RuntimeUnitTestToolkit\.csproj
+
+Assembly-CSharp-Editor\.csproj
+
+UniRx\.Async\.unitypackage
diff --git a/Assets/Editor.meta b/Assets/Editor.meta
new file mode 100644
index 0000000..1d140d4
--- /dev/null
+++ b/Assets/Editor.meta
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 99c8676e874bf0343b421d3527868f16
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/Editor/PackageExporter.cs b/Assets/Editor/PackageExporter.cs
new file mode 100644
index 0000000..0d034bd
--- /dev/null
+++ b/Assets/Editor/PackageExporter.cs
@@ -0,0 +1,35 @@
+#if UNITY_EDITOR
+
+using System;
+using System.IO;
+using System.Linq;
+using UnityEditor;
+using UnityEngine;
+
+public static class PackageExporter
+{
+    [MenuItem("Tools/Export Unitypackage")]
+    public static void Export()
+    {
+        // configure
+        var root = "UniRx.Async";
+        var exportPath = "./UniRx.Async.unitypackage";
+
+        var path = Path.Combine(Application.dataPath, root);
+        var assets = Directory.EnumerateFiles(path, "*", SearchOption.AllDirectories)
+            .Where(x => Path.GetExtension(x) == ".cs" || Path.GetExtension(x) == ".asmdef" || Path.GetExtension(x) == ".json")
+            .Select(x => "Assets" + x.Replace(Application.dataPath, "").Replace(@"\", "/"))
+            .ToArray();
+
+        UnityEngine.Debug.Log("Export below files" + Environment.NewLine + string.Join(Environment.NewLine, assets));
+
+        AssetDatabase.ExportPackage(
+            assets,
+            exportPath,
+            ExportPackageOptions.Default);
+
+        UnityEngine.Debug.Log("Export complete: " + Path.GetFullPath(exportPath));
+    }
+}
+
+#endif
\ No newline at end of file
diff --git a/Assets/Editor/PackageExporter.cs.meta b/Assets/Editor/PackageExporter.cs.meta
new file mode 100644
index 0000000..1261cdd
--- /dev/null
+++ b/Assets/Editor/PackageExporter.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: af97405af79afbb4e9f7f49f30088474
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: