A supersonic beauty treatment device capable of effecting a beauty treatment for the skin and of slimming a selected portion of the body. Here, a battery for generating a battery supply voltage and a step-up converter for generating an intermediate voltage from the battery supply voltage are provided. The bag chute includes a shoulder at an upper end of the chute to hang the bag chute from the bag support and can also include a vertical slot on a front side of the chute that extends down from the upper end of the chute about half the length of the chute. Furthermore, a voltage monitoring circuit is provided that works independent of the oscillator, inhibiting the output voltage of the oscillator when the voltage on the output of the blocking-oscillator-type converter is too large.