Disclosed is an ultrasonic transducer which is composed of a plurality of piezoelectric elements having an electrode on each of two opposite surfaces, an acoustic matching layer arranged on the first surface that is one of the two opposite surfaces, a wiring board so arranged on the acoustic matching layer as to be in contact with the piezoelectric element, and a conductor electrically connecting the wiring board with the electrode on the second surface that is one of the two opposite surfaces. This ultrasonic transducer is characterized in that the surface of the wiring board on the same side as the second surface of the piezoelectric element is positioned relatively lower than the second surface of the piezoelectric element.