diff --git a/README.rst b/README.rst
index 4ef4f61..a9ec091 100644
--- a/README.rst
+++ b/README.rst
@@ -68,6 +68,15 @@
     enabled: true
     config:
       label:
+        elasticsearch_output:
+          match:
+            elasticsearch_output:
+              tag: "**"
+              type: elasticsearch
+              host: 10.100.0.1
+              port: 9200
+              buffer:
+                flush_thread_count: 8
         monitoring:
           filter:
             parse_log:
diff --git a/fluentd/files/buffer/file.conf b/fluentd/files/buffer/file.conf
index b71370f..a9b7c9a 100644
--- a/fluentd/files/buffer/file.conf
+++ b/fluentd/files/buffer/file.conf
@@ -20,4 +20,7 @@
     {%- if values.get("compress") %}
     compress {{ values.get("compress") }}
     {%- endif %}
+    {%- if values.get("flush_thread_count") %}
+    flush_thread_count {{ values.get("flush_thread_count") }}
+    {%- endif %}
 {% include "fluentd/files/buffer/_general.conf" %}