diff --git a/DNSecure/ContentView.swift b/DNSecure/ContentView.swift
index f5b1e14..f3e32c7 100644
--- a/DNSecure/ContentView.swift
+++ b/DNSecure/ContentView.swift
@@ -35,7 +35,7 @@ struct ContentView {
         let manager = NEDNSSettingsManager.shared()
         manager.loadFromPreferences {
             if let err = $0 {
-                print("\(err.localizedDescription)")
+                logger.error("\(err.localizedDescription)")
             } else {
                 self.isEnabled = manager.isEnabled
             }
@@ -46,7 +46,7 @@ struct ContentView {
         let manager = NEDNSSettingsManager.shared()
         manager.loadFromPreferences { loadError in
             if let loadError = loadError {
-                print("\(loadError.localizedDescription)")
+                logger.error("\(loadError.localizedDescription)")
                 return
             }
             manager.dnsSettings = self.usedID
@@ -56,10 +56,10 @@ struct ContentView {
                 .map { $0.toDNSSettings() }
             manager.saveToPreferences { saveError in
                 if let saveError = saveError {
-                    print("\(saveError.localizedDescription)")
+                    logger.error("\(saveError.localizedDescription)")
                     return
                 }
-                print("saved")
+                logger.debug("DNS settings are saved")
             }
         }
     }
diff --git a/DNSecure/DNSecureApp.swift b/DNSecure/DNSecureApp.swift
index 217ac01..3366b84 100644
--- a/DNSecure/DNSecureApp.swift
+++ b/DNSecure/DNSecureApp.swift
@@ -5,8 +5,11 @@
 //  Created by Kenta Kubo on 7/1/20.
 //
 
+import os
 import SwiftUI
 
+let logger = Logger()
+
 @main
 struct DNSecureApp {}