An electromechanical transducer includes a vibration membrane provided with a first electrode, a substrate provided with a second electrode, and a support member adapted to support the vibration membrane in such a manner that a gap is formed between the vibration membrane and the substrate, with the first and second electrodes being arranged in opposition to each other, wherein a part of the vibration membrane and a part of the substrate are in contact with each other at a contact region, and another region of the vibration membrane other than the contact region is able to vibrate; an overlap region is provided between the first electrode and second electrode in the contact region, and at least one of these electrodes has a through portion formed therethrough in at least a part of the overlap region, and a plurality of protrusions formed within the gap and on at least one of the vibration member and the support member, wherein the contact region is surrounded by the plurality of protrusions.