diff --git a/fluentd-monasca-output.gemspec b/fluentd-monasca-output.gemspec
index ae85448..05a0487 100644
--- a/fluentd-monasca-output.gemspec
+++ b/fluentd-monasca-output.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |spec|
   spec.test_files = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
 
-  spec.add_runtime_dependency 'fluentd', '>= 0.10.43', '<0.14'
+  spec.add_runtime_dependency 'fluentd', '>= 0.10.43'
   spec.add_runtime_dependency 'rest-client', '~> 2.0'
   spec.add_runtime_dependency 'yajl-ruby', '~> 1.4', '>= 1.4.1'