PURPOSE: To keep the always stable vibration by regulating each attenuation means interlockingly so as to decrease the attenuation of one attenuation means when the attenuation of other attenuation means is increased.

CONSTITUTION: The attenuators 4, 6 are mutually interlocked and the attenuation of the attenuator 6 at the input side of the oscillation circuit 1 is increased in interlocking with the regulation of the attenuator 4 in increasing the amplitude of the vibrator 3 by decreasing the attenuation of the attenuator 4. Since the amplitude of vibration is attenuated and then a feedback input is applied to the oscillation circuit 1, waveform distortion or excess growth of vibration leading to the destruction of components is prevented. Moreover, the attenuation of the attenuator 4 is increased to decrease the amplitude of the vibrator 3, then the attenuation of the attenuator 6 at the input side of the oscillation circuit 1 is decreased interlockingly. Thus, a feedback input is given to the oscillation circuit 1 without exerting much attenuation to the amplitude vibration thereby avoiding the production of an event resulting in stopping the vibration due to the gradual decrease in the vibration. Thus, the vibrator is vibrated at a stable frequency and the vibration controller whose amplitude of vibration is varied optionally is obtained with simple constitution.