A transmitting, focusing, ultrasonic wave transducer (20) is excited by high-frequency pulses sent from a high-frequency pulse generator (1); the leakage elastic surface waves are excited in a sample (6) by the focusing ultrasonic wave beams of the transducer (20); the waves emitted again are received by a receiving focusing ultrasonic wave transducer (24); the received signals are sent to a mixer (23) where a difference in phase is detected relative to reference signals produced from a high-frequency oscillator (18) in the high-frequency pulse generator (1); and the detected output is supplied as a display signal to a display (9 or 14). The transducers (20, 24) and the sample (6) are relatively moved by a moving device (7 or 10) two-dimensionally on a plane parallel to the surface of the sample or at right angles to the surface of the sample. In synchronism with this movement, the surface of the display (9 or 14) is swept to obtain an ultrasonic microscopic image or a V(z) curve on the display surface.