diff --git a/README.md b/README.md
index e3ef786..dae40a9 100644
--- a/README.md
+++ b/README.md
@@ -20,16 +20,19 @@ $ cat example/data.json
         {
             "id": "id-A",
             "count": 1,
+            "some_boolean": true,
             "state": "ACTIVE"
         },
         {
             "id": "id-B",
             "count": 2,
+            "some_boolean": true,
             "state": "INACTIVE"
         },
         {
             "id": "id-C",
             "count": 3,
+            "some_boolean": false,
             "state": "ACTIVE"
         },
     ]
@@ -50,20 +53,25 @@ $ cat example/config.yml
   values:
     active: 1      # static value
     count: $.count # dynamic value
+    boolean: $.some_boolean
 
 $ python -m SimpleHTTPServer 8000 &
 Serving HTTP on 0.0.0.0 port 8000 ...
 
 $ ./json_exporter http://localhost:8000/example/data.json example/config.yml &
 INFO[2016-02-08T22:44:38+09:00] metric registered;name:<example_global_value>
+INFO[2016-02-08T22:44:38+09:00] metric registered;name:<example_value_boolean>
 INFO[2016-02-08T22:44:38+09:00] metric registered;name:<example_value_active>
 INFO[2016-02-08T22:44:38+09:00] metric registered;name:<example_value_count>
 127.0.0.1 - - [08/Feb/2016 22:44:38] "GET /example/data.json HTTP/1.1" 200 -
 
+
 $ curl http://localhost:7979/metrics | grep ^example
 example_global_value{environment="beta"} 1234
 example_value_active{environment="beta",id="id-A"} 1
 example_value_active{environment="beta",id="id-C"} 1
+example_value_boolean{environment="beta",id="id-A"} 1
+example_value_boolean{environment="beta",id="id-C"} 0
 example_value_count{environment="beta",id="id-A"} 1
 example_value_count{environment="beta",id="id-C"} 3
 ```
diff --git a/example/config.yml b/example/config.yml
index d4c62db..e886ab2 100644
--- a/example/config.yml
+++ b/example/config.yml
@@ -12,3 +12,4 @@
   values:
     active: 1      # static value
     count: $.count # dynamic value
+    boolean: $.some_boolean
diff --git a/example/data.json b/example/data.json
index 45e2b79..b672989 100644
--- a/example/data.json
+++ b/example/data.json
@@ -4,16 +4,19 @@
         {
             "id": "id-A",
             "count": 1,
+            "some_boolean": true,
             "state": "ACTIVE"
         },
         {
             "id": "id-B",
             "count": 2,
+            "some_boolean": true,
             "state": "INACTIVE"
         },
         {
             "id": "id-C",
             "count": 3,
+            "some_boolean": false,
             "state": "ACTIVE"
         },
     ]