An ultrasound surgical apparatus 1 includes a handpiece 40 which includes a probe 30 provided with a proximal end portion 32 mechanically coupled to an ultrasound transducer 35 and a distal end portion 21 used for treatment of a living tissue； a drive portion 32 which outputs a drive signal； a detection portion 25 which detects, in the drive signal, a cavitation level signal corresponding to a state of cavitation generated in a calibration solution 51, based on the drive signal of calibration signal strength corresponding to class information about the handpiece 40； a condition storage portion 26 which stores calibration information； an output setting portion 24 which sets the vibration strength； and a control portion 23 which controls the drive portion 22 so as to output the drive signal of drive signal strength corresponding to the vibration strength set by the output setting portion 24, based on the calibration information and the class information.
