A speaker and the like, which is capable of wideband reproduction by improving the bass characteristic, and which is suitable for size reduction, is provided.
A housing (110) includes one main surface (111) having a polygonal shape, and an opening portion (112) in the one main surface. A diaphragm (120) is disposed in the opening portion so as to cover the one main surface, except for corner regions (115a, 115b, 115c, and 115d) which are areas in the vicinity of respective vertices of a polygonal shape of the one main surface. A driving unit (130) causes the diaphragm to vibrate so as to generate a sound corresponding to a signal inputted from an outside. A plurality of movable supports (140a, 140b, 140c, and 140d) is disposed in the respective corner regions, for supporting the diaphragm by joining the housing and the diaphragm such that the diaphragm is vibratable.