diff --git a/Cargo.toml b/Cargo.toml
index 3cb90d0..776e51e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "slack-rust"
-version = "0.1.0"
+version = "0.1.0-alpha"
 authors = ["Gompei <shoueigonpei6028@gmail.com>"]
 edition = "2018"
 description = "Slack API Client"
diff --git a/README.md b/README.md
index 225cd04..3fc7efe 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ Add this to your Cargo.toml:
 
 ```toml
 [dependencies]
-slack_rust = "0.1"
+slack_rust = "0.1.0-alpha"
 ```
 
 ### [Web API](https://api.slack.com/methods)