An ultrasound operation apparatus 21 includes an ultrasound transducer Ib； an ultrasound drive section 5 that drives the ultrasound transducer Ib by means of a drive signal； a probe 2a that has a proximal end section in which the ultrasound transducer Ib is provided and a distal end section Ie to which ultrasound vibrations are transmitted, and that performs treatment for living tissue by using ultrasound vibrations at the distal end section Ie； a detection section 38 that detects from the drive signal a physical quantity that changes due to cavitations generated by ultrasound vibrations of the distal end section Ie； and a CPU 40 that controls the output of the ultrasound drive section 5 so as to generate cavitations or to increase or maintain a generation amount in accordance with the detected physical quantity.
