A vibrating alert device not startling the user by its vibration and able to improve the effectiveness of the alert, provided with a vibration strength control circuit becoming active for a duration of an incoming call signal and repeatedly gradually increasing a drive voltage supplied to the vibrating motor in stages from a minimum vibration strength voltage to a maximum vibration strength voltage, the vibration control circuit having a resistance type voltage division circuit which generates different vibration strength voltages from a minimum voltage strength voltage to a maximum voltage strength and a voltage switching circuit for selecting and outputting in a rising order the vibration strength voltages for each constant time.