The present invention relates to an ultrasonic surgical device in which a cartridge comprises: a cartridge housing having an empty inner space filled with a medium； an ultrasonic therapy part which is movably provided inside the cartridge housing and includes a transducer for generating focused ultrasonic waves； a window through which the ultrasonic waves generated from the transducer pass； and a driving part which moves the ultrasonic therapy part inside the cartridge housing, wherein, as the transducer moves in one direction, the distance between the window and the transducer repeatedly increases and decreases.
