Ultrasonic surgical device 21 transmits an ultrasonic drive unit 5 and the ultrasonic transducer Ib, driven by the drive signal to the ultrasonic transducer Ib, ultrasonic vibration and the proximal end of the ultrasonic transducer Ib is provided a probe 2 for treatment on living tissue by ultrasonic vibration of the tip portion and a tip portion that is, the resonance frequency tracking unit 37 for driving so as to ultrasonic vibration at the resonance frequency, the resonance frequency than the drive signal I provided the cavitation suppression control unit 40a for detection and control unit 38 has a function of the filter unit 39 which detects the frequency component signal of the frequency components of, in accordance with the detection results, so as to eliminate or suppress the cavitation.超音波手術装置21は、超音波振動子Ibと、超音波振動子Ibを駆動信号により駆動する超音波駆動装置5と、超音波振動子Ibが設けられた基端部及び超音波振動が伝達される先端部とを有し先端部での超音波振動により生体組織に対する処置を行うプローブ2と、共振周波数で超音波振動させるように駆動する共振周波数追尾部37と、駆動信号の共振周波数以外の周波数成分の周波数成分信号を検出するフィルタ部39の機能を有する検出部38と、検出結果に従い、キャビテーションを抑制または消滅させるように制御するキャビテーション抑制制御部40aとを具備する。
