A moving object 1 equipped with ultra-directional speaker is provided with an emitter 44 for measuring a distance to a target 11 to which it is to provide a voice by using an ultrasonic transmit sensor 45 and an ultrasonic receive sensor 46 thereof, and for emitting an output signal having a predetermined sound level which is adjusted by an amplifier 34 with sound level adjusting function. The moving object 1 can thus transmit a voice having an optimal volume only to the specific target through parametric action.