An ultrasonic aspirator has a probe having the inside path made an aspirating path by being provided on the base side with an ultrasonic vibrator. The probe is used as an ultrasonic vibration transmitting member and is in contact at the tip with an object within a body cavity to crush the object and to discharge the crushed object out of the probe through the aspirating path. A device, for detecting a break of the probe, is provided so that, when the probe breaks, the vibration of the above mentioned ultrasonic vibrator will be stopped by a signal from the detecting device.