diff --git a/BrotherPrinterDocument.cs b/BrotherPrinterDocument.cs
index d33eaf6..156473f 100644
--- a/BrotherPrinterDocument.cs
+++ b/BrotherPrinterDocument.cs
@@ -63,7 +63,7 @@ public void Print(Dictionary<string, string> fields)
 				var field = document.GetObject(e.Key);
 				if (field == null)
 				{
-					Console.WriteLine("[ERROR] field is undefined. key: [{0}]", e.Key);
+					MyLogger.Error("フィールド [{0}] が未定義です。", e.Key);
 					continue;
 				}
 
@@ -86,8 +86,6 @@ public void Close()
 			// this._document.EndPrint();
 
 			this._document.Close();
-
-			// Console.WriteLine("[DEBUG] プリンターオブジェクトが解放されました。");
 		}
 
 		/// <summary>
diff --git a/ConfigurationManager.cs b/ConfigurationManager.cs
index e36c05b..981a5c4 100644
--- a/ConfigurationManager.cs
+++ b/ConfigurationManager.cs
@@ -87,8 +87,8 @@ public static ConfigurationManager Configure()
 				}
 			}
 
-			Console.WriteLine("--dryrun: " + conf.dryrun);
-			Console.WriteLine("--address-file: " + string.Join(", ", conf.addressFiles));
+			MyLogger.Info("--dryrun: [", conf.dryrun, "]");
+			MyLogger.Info("--address-file: [", string.Join(", ", conf.addressFiles), "]");
 
 			return conf;
 		}
diff --git a/MyLogger.cs b/MyLogger.cs
new file mode 100644
index 0000000..5c83b9b
--- /dev/null
+++ b/MyLogger.cs
@@ -0,0 +1,44 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace PtouchPrintSender
+{
+    class MyLogger
+    {
+        private MyLogger()
+        {
+
+        }
+
+        //public static void Info(string format, params object[] args)
+        //{
+        //    var timestamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
+        //    var line = string.Format(format, args);
+        //    Console.WriteLine($"{timestamp} [INFO] {line}");
+        //}
+
+        public static void Info(params object[] args)
+        {
+            var timestamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
+            var line = string.Join("", args);
+            Console.WriteLine($"{timestamp} [INFO] {line}");
+        }
+
+        //public static void Error(string format, params object[] args)
+        //{
+        //    var timestamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
+        //    var line = string.Format(format, args);
+        //    Console.WriteLine($"{timestamp} [ERROR] {line}");
+        //}
+
+        public static void Error(params object[] args)
+        {
+            var timestamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
+            var line = string.Join("", args);
+            Console.WriteLine($"{timestamp} [ERROR] {line}");
+        }
+    }
+}
diff --git a/Program.cs b/Program.cs
index c4921a0..8646a74 100644
--- a/Program.cs
+++ b/Program.cs
@@ -19,15 +19,19 @@ public static void Main(string[] args)
 		{
 			try
 			{
+				MyLogger.Info("### START ###");
+
 				// コンフィギュレーション
 				var conf = ConfigurationManager.Configure();
 
 				// アプリケーションを実行
 				new Application().Run(conf);
+
+				MyLogger.Info("--- END ---");
 			}
 			catch (Exception e)
 			{
-				Console.WriteLine("[ERROR] 予期しない実行時エラーです。" + e);
+				MyLogger.Error("予期しない実行時エラーです。" + e);
 			}
 		}
 	}