Provided is an authenticating apparatus that by a simple method improves security when entering a password. The authentication-processing unit executes user authentication by comparing an entered password that is entered with a preset set password. The input-receiving unit receives dummy keys while the entered password is entered that are not compared with the set password. The dummy-input-notification unit notifies using vibration of dummy key input timing and the number of times input is required. The authentication-processing unit, together with comparing the entered password with the set password, compares the number of times dummy keys are inputted with the number of times input is required. When the entered password and the set password match, and the number of times dummy keys are inputted and the number of times input is required match, authentication is determined to be successful.