PURPOSE: To make it possible to obtain balanced stereophonic reproduced sound by providing side speakers provided in the front and left and right sides of listeners arranged in a row and reproducing left and right channel signals corresponding to stereophonic sound sources, a center speaker that reproduces both channel signals of stereophonic sound sources and a delaying device that gives a specified delay time to both channel signals inputted to the center speaker.

CONSTITUTION: R channel sound is radiated from the side speaker 20(R) positioned at the front right side to a rider M1, and L and R channel sound is radiated from the first and second center speakers 22(R), 23(L). At this time, R channel sound component which is the same channel as the sound of the first side speaker 20(R), i.e., the sound of the first center speaker 22(R) acts on the ear of the rider M1 as if it were reverberation to the sound of the first side speaker 20(R). The sound of L channel of the second center speaker 23(L) is actualized and reaches dominantly the left ear of the rider. Stereophonic sensation can be obtained by the first side speaker 20(R) that radiates R channel sound and the second center speaker 23(L) that delays and radiates left channel sound.