Abstract

In a shock wave generating apparatus, phase shifts contained in echo signals reflected from a calculus are corrected in order to clearly judge whether or not such a calculus is actually present at a focal point or a near region. The shock wave generating apparatus includes: a shock wave producing unit constructed of at least two transducer elements, for producing shock wave pulses used to disintegrate an object located near a focal point of said shock wave producing unit within a biological body under medical examination upon receipt of first drive pulses having first energy levels, and also for producing ultrasonic pulses used to obtain echo pulses reflected from said object near the focal point, as echo signals, upon receipt of second drive pulses having second energy levels lower than said first energy levels of the first drive pulses; an analog type phase-shift correcting unit for correcting phase shifts contained in the echo signals reflected from the object near the focal point by making respective phases of the echo signals coincident with each other as to a time domain of the analog echo signals, thereby obtaining an analog phase-corrected echo signal; a peak detecting unit for detecting a peak value of the analog phase-corrected echo signal; and a controlling unit for controlling the shock wave producing unit based on the peak value of the analog phase-corrected echo signal to determine whether or not the shock wave pulses are produced in order to destroy the object near the focal point.