An ultrasound operation apparatus 21 comprises: an ultrasound transducer Ib； a driving section 66 that drives the ultrasound transducer Ib by a drive signal； a probe Ia having a proximal end section provided with the ultrasound transducer Ib and a distal end section Ie to which ultrasound oscillation is transmitted, the probe performing a treatment on a living tissue using ultrasound oscillation at the distal end section Ie； a detecting section 38 that detects, from a drive signal, a physical quantity which varies due to cavitation generated by ultrasound oscillation of the distal end section Ie； and a CPU 40 that controls an output of the driving section in accordance with the detected physical quantity.
