diff --git a/datetimerange/__version__.py b/datetimerange/__version__.py
index ce1ba96..f4e19d7 100644
--- a/datetimerange/__version__.py
+++ b/datetimerange/__version__.py
@@ -1,6 +1,6 @@
 __author__ = "Tsuyoshi Hombashi"
 __copyright__ = "Copyright 2016, {}".format(__author__)
 __license__ = "MIT License"
-__version__ = "0.6.1"
+__version__ = "1.0.0"
 __maintainer__ = __author__
 __email__ = "tsuyoshi.hombashi@gmail.com"