A subtractor subtracts an echo canceling signal Ĉ·y1(n−1) from a canceling error signal e(n) to estimate a residual noise to be silenced at the position of a microphone, and outputs a first basic signal x1(n) representing the residual noise. A first control circuit section generates a first control signal y1(n) based on the first basic signal x1(n) and a second basic signal x2(n) that is generated by delaying the first basic signal x1(n) by a time Z−n. A second circuit section generates a second control signal y2(n) based on the first basic signal x1(n) and an engine rotation signal.