When a listener 10 changes the reclining angle of a backrest part 101a of a seat 101 and a head 10a of the listener 10 is thereby caused to be present outside an audible area 120a of a directional loudspeaker 120 or when the reclining angle of a front seat 100 is changed and the head 10a of the listener 10 is thereby caused to be present outside the audible area 120a of the directional loudspeaker 120, a distance L2 to an obstacle exceeds 1 m as an upper limit of a standard listening range and it is determined that the head 10a of the listener 10 is present beyond the standard listening range, and the audio output of the directional loudspeaker 120 is stopped.