To provide an ultrasonic slimming device, having an effect for a lean figure and radiating ultrasonic waves under safe conditions not to affect the internal organs or the like in the deepest regions of the body.

This ultrasonic slimming device includes: an ultrasonic wave generating part 3 having an ultrasonic vibrator 2 and radiating ultrasonic waves toward a desired region 6 of the body 5 with the vibrator applied to the region; and a control part 4 for controlling the ultrasonic vibrator 2. The frequency of an ultrasonic wave radiated from the ultrasonic wave generating part 3 is set to 0.7 MHz or more, the radiation power when the frequency is within the range from 0.7 to 1.3MHz is set to 0.8W/cm2 or less, and the radiation power when the frequency exceeds 1.3MHz is set to 3W/cm2 or less.