Included are a first obtainer which obtains a first signal output from a first microphone, a second obtainer which obtains a second signal output from a second microphone installed in a position different from a position where first microphone is installed, a delayer which delays the second signal, a mixed sounds estimator which estimates noises mixed in the first signal on the basis of the second signal delayed by the delayer, and an eraser which erases the noises from the first signal, the noises being estimated by the mixed sounds estimator.