A sound determination unit previously divides sound into a low sound range for first sound, a middle sound range for second sound, and a high sound range for third sound by its frequency band. When sound information detected by the microphone is inputted to the sound determination unit, the sound determination unit determines whether the frequency band of that sound information is in the predetermined low sound range or not. When it is in the low sound range, a signal to operate a first vibrator is generated from a first controller. When it is in the middle sound range, a signal to operate a second vibrator is generated from a second controller. When it is in the high sound range, a signal to operate a third vibrator is generated from a third controller.