An ultrasonic speaker or acoustic system includes an electrostatic type ultrasonic transducer of a push-pull system is constructed such that a through hole is arranged in the central portion of a fixing electrode of a circular shape. A sound wave reflecting plate is arranged on the rear face of the ultrasonic transducer and an ultrasonic wave radiated from the rear face of the ultrasonic transducer is reflected by the sound wave reflecting plate and is radiated to the front face of the ultrasonic transducer through the through hole.