TRANSDUCER

A transducer includes a substrate containing silicon and a piezoelectric element disposed on the substrate. The substrate includes a film body including a first surface and a second surface facing in mutually opposite directions in a thickness direction of the substrate and a frame body surrounding the film body when the film body is viewed from the thickness direction. The piezoelectric element is disposed on the first surface of the film body. A part of an outer edge of the film body when viewed from the thickness direction forms a connection portion connected to the frame body, and a remaining part of the outer edge excluding the connection portion is separated from the frame body. The substrate includes a protrusion protruding in the thickness direction from a region including at least a part of the remaining part of the outer edge of the second surface.