Abstract

An apparatus for destroying a calculus includes an ultrasonic wave generating unit capable of setting a plurality of piezo-electric devices in a drive/reception mode by phase control, a peak value detecting unit for detecting a peak value, in a predetermined time width, of an echo signal in a reception signal received by the piezo-electric devices, a first comparing unit for comparing the peak value detected by the peak value detecting unit with a first predetermined threshold value, a frequency analyzing unit for analyzing a frequency component, in the predetermined time width, of the echo signal in the reception signal, a calculating unit for calculating a predetermined characteristic value on the basis of frequency component data obtained by the frequency analyzing unit, a second comparing unit for comparing the characteristic value obtained by the calculating unit with a second predetermined threshold value, and a display unit for displaying a comparison result of the first comparing unit with a comparison result of the second comparing unit.