An ultrasound operation system 1 includes an output transformer Tr, a hand piece 2 including an object to be driven including an ultrasound transducer 2f which is driven by the output transformer Tr and a treatment portion 2e which is connected to the ultrasound transducer 2f to perform treatment of a living tissue by an ultrasound vibration generated in the ultrasound transducer 2f, and a non-inductive resistor R2 which is provided between the output transformer Tr and the ultrasound transducer 2f, and perform regulation of an amplitude of the ultrasound transducer 2f by diverting a current which flows into the ultrasound transducer 2f from the output transformer Tr in accordance with a state of a load exerted on the treatment portion 2e and regulating an amount of a current which flows into the ultrasound transducer 2f.
