PURPOSE: To prevent the scattering of high-pressure water and the generation of noise by putting a member to be washed, nozzles, etc., in a water tank and carrying out washing work in water with high-pressure water from the nozzles.

CONSTITUTION: A nozzle truck 2 is disposed on a base main body 1 and a nozzle stand 9 fitted with nozzles 8 is disposed on the truck 2. A supporting truck 4 is set at one end of the base 1, a supporting roll 3 fitted with a rotating device is set at the other end and a pressing roll 6 is put on the roll 3. In order to bury them in water, a water tank 7 is installed. A member 5 to be washed is rotatably supported by the truck 4 and the roll 3 under restraint from the top by the roll 6, water is filled into the tank 7 and high-pressure water is jetted from the nozzles 8 to wash the member 5 in the filled water. The scattering of high-pressure water and the generation of noise can be prevented.