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