A speaker includes a magnetic circuit, a voice coil, and a diaphragm which are disposed in a case. The case is placed in an engine compartment of an automobile. Reproduced sound is emitted through a duct protruding outward from the case. A partition wall, which is a metal body frame of the automobile, is present between the engine compartment and the cabin space. The duct is inserted into a hole formed in the partition wall so that a sound port faces and protrudes into the cabin space. A heat dissipation port is formed in the case, and an end surface the magnetic circuit facing the partition wall is exposed in the heat dissipation port. An elastically deformable thermal conductive sheet is sandwiched between the partition wall and the end surface of the magnetic circuit.