An active silencer includes: a speaker generating control sound which interferes with noise； a microphone detecting noise remaining after the interference as a remaining noise signal； a sound quality evaluation unit evaluating the sound quality of the remaining noise and output a result of the sound quality evaluation； an actuation signal determination unit determining, according to the result of the sound quality evaluation, the detection timing of the frequency component of the remaining noise signal to be used when the control sound is generated for a plurality of bands of the remaining noise, corresponding to the plurality of bands of a reference signal corresponding to the noise； and a control signal generation unit generating and output a control signal for generation of the control sound depending on a plurality of bands of the determined remaining noise signal and a plurality of bands of the reference signal corresponding to the noise.
