This headphone type acoustic apparatus includes a pair of housing blocks each including a headphone unit, a headband section that supports the housing blocks at both ends and includes a pair of speaker units, one or more sensors that obtain information for estimating a mounted state achieved by a user, and a control unit that estimates the mounted state based on outputs of the one or more sensors and controls, based on the estimated mounted state, outputs of the pair of headphone units and the pair of speaker units.