PURPOSE: To make efficient chipping with less noise available without affecting the depths of concrete by ejecting ultrahigh-pressure water from a nozzle provided on a lifting device installed on a vehicle, and by moving the nozzle by lifting up and down the lifting device and by moving the vehicle.

CONSTITUTION: A supporting stand 21 is fixed to a vehicle 3, a lifting device 31 is fixed to the supporting stand 21 and a work bench 41 is fixed to an upper stage 32 of the lifting device 31. To the front of the work bench 41, a nozzle 13 is turnably fixed through a fixing member 43 and an adjustable thrust bearing 15. High-pressure water is supplied to the nozzle 13 through a high-pressure hose 14. Then chipping is carried out with the high-pressure water blown against a wall 2, while the nozzle 13 is made to go up and down by the lifting device 31 and the vehicle 3 is made to travel along the wall surface.