diff --git a/sample.properties b/sample.properties
index d3305c4..1cdd664 100644
--- a/sample.properties
+++ b/sample.properties
@@ -4,3 +4,6 @@ API_BASE_URL     = https://partnerapi-sandbox.pokepay.jp
 
 PKCS12_FILE      = certkey.p12
 PKCS12_PASSWORD  = changeit
+
+ACCEPT-LANGUAGE = en
+
diff --git a/src/main/java/jp/pokepay/partnerapi/Config.java b/src/main/java/jp/pokepay/partnerapi/Config.java
index 6281397..7eae1a6 100644
--- a/src/main/java/jp/pokepay/partnerapi/Config.java
+++ b/src/main/java/jp/pokepay/partnerapi/Config.java
@@ -30,6 +30,6 @@ public Config(File file) throws ConfigFileNotFoundException, ProcessingError {
         this.baseUrl = properties.getProperty("API_BASE_URL");
         this.p12File = file.toPath().getParent().resolve(properties.getProperty("PKCS12_FILE")).toString();
         this.p12Password = properties.getProperty("PKCS12_PASSWORD");
-        this.acceptLanguage = properties.getProperty("ACCEPT-LANGUAGE", "jp");
+        this.acceptLanguage = properties.getProperty("ACCEPT-LANGUAGE", "en");
     }
 }