To provide a sounder contained in a small-sized wireless unit, such as a cellular phone that can be contained in a small volume and emits sound in the forward direction.

In the small-sized wireless unit, containing the sounder 1 emitting sound in front of a case in the inside of the thin case, a vibrating direction of a diaphragm 7 of the sounder 1 is selected to be the thickness direction of a housing 2 of the sounder 1, and a sound emission port 14 is provided to a side of the housing 2. The sounder 1 can be contained in a small space, and the sound is emitted forward of the case. Accordingly, the sounder can cope with the downsizing as a whole.