A speaker has a pipe member with opposed open ends, and a sounding body that is attached to any one of the opposed open ends of the pipe member on the same axle as that of the pipe member. The sounding body is driven on the basis of an acoustic signal that is applied to the sounding body. Sound wave radiated from the sounding body and passed through an inside of the pipe member vibrates with a pipe wall of the pipe member, thereby to enable sound wave corresponding to the acoustic signal to radiate from a whole of an outside surface of the pipe member to outside.