An acoustic apparatus includes a sound-emitting unit that acoustically outputs a sound signal, at least one sensor that periodically detects accelerations of the user in three directions including a front-rear direction, a left-right direction, and an upper-lower direction, a vibration sound peak detection unit detecting a peak of a vibration sound based on a movement of the user when detection values of the accelerations in the front-rear direction, the left-right direction, and the upper-lower direction satisfy a predetermined condition, and a signal processing unit that determines whether a time difference at which the peak of the vibration sound is detected is periodic. When it is determined that the time difference is periodic, the signal processing unit sets a gain of a cancellation signal to be suppressed from the sound signal acoustically output from the sound-emitting unit based on the peak of the vibration sound.