PURPOSE: To attain the silencing of a selective sound and to simplify the maintenance and inspection of the device because a microphone which has a little durability isn't used by detecting the oscillation of a noise generating source so as to make a control sound.

CONSTITUTION: On the cylinder head 12 of an internal combustion engine 11 an accelerating pickup 13 is attached as the detector of oscillation and the oscillation signal (v) of the engine from the accelerating pickup 13 is conducted to a filter 14. And in the filter 14 a control signal (e) is made and amplified in an amplifier 15 to drive a speaker 16, so that a control sound is emitted into an exhaust pipe 17. Now a microphone 18 for detecting the residual value (r) of the exhaust noise at the end of the exhaust pipe 17 is used so as to decide the characteristic of the filter 14 and if the characteristic of the filter is decided once the microphone 18 isn't needed.