A cartridge for a high intensity focused ultrasound (HIFU) device and a piezoelectric linear motor are disclosed. By using the cartridge for a HIFU device according to the present invention, a transducer module is coupled to a piezoelectric linear motor driveable in water and embedded in the cartridge, heat generated when a conventional step motor is driven is fundamentally removed, an additional cooling fan is not needed, ultra-low power consumption and ultra-precise transfer can be realized, and thus an effective procedure can be performed. A skin beauty device may include ultrasound and high frequency units, apply a high frequency to a skin to be treated so as to crack a stratum corneum, and apply ultrasound to the skin to be treated, and thus a medicament drug can easily penetrate the treated skin. In addition, the piezoelectric linear motor in which a piezoelectric actuator and a moving shaft are stably coupled is provided.