To keep high cleaning capacity by lasting emission of ultrasonic vibration stably for a long period of time.

A housing 25 having a nozzle hole 24 is divided into the first space 26 communicating with the hole 24 and the second space 27 by a vibratory partition plate 28. The housing 25 is provided with a cleaning liquid supplying means 29 for sending a cleaning liquid to the space 26 forcibly and a fluid supplying means 30 for supplying an incompressible fluid to the space 27 to fill the space 27 with it. A vibrating element 31 arranged in the housing 25 to face to the space 27 is vibrated ultrasonically by a vibrating means 32 and the ultrasonic vibration of the element 31 is propagated to the plate 28 through the incompressible fluid to be supplied into the space 27 for cooling the element 31.