To obtain a silencer which can reduce coefficient update calculation quantity of an adaptive filter in noise control operation when plural noises exist.

Microphones 1a-1d for detecting a noise is arranged at a noise generation source, and a microphone 2 for detecting an error is arranged at a control point. Adaptive filters 3a-3d inputs a noise signal of the microphones 1a-1d and generate a silencing signal. At the time, a FIR FILTER 8 performs signal processing from a noise selected by a switch 6, and corrects a coefficient. Also, a LMS computing element 9 processes an error signal of the microphone 2 using a method of least squares, and calculates an optimum tap coefficient. This calculated result is periodically switched by a switch 7, and it is given to the adaptive filters 3a-3d. Each control signal processed by the adaptive filters 3a-3d is added by an adder 4, and a control sound is outputted from a loudspeaker 5.