An acoustic device including: a vibrating film which has waterproofness; a support which is located alongside the vibrating film in a direction and supports the vibrating film; a waterproof which is in contact with the support; an insulating plate which is located on an opposite side of the waterproof to a side where the support is arranged, and which has a first through hole leading to the vibrating film; and a metal plate which is located on an opposite side of the insulating plate to the waterproof, which has a second through hole communicating with or containing the first through hole, and which is fixed in a state pressing the insulating plate along the direction.