PURPOSE: To simplify structure and to sufficiently guide a nozzle along the inner circumferential wall even if the inside diameter of piping is small by constituting the device of a nozzle support body at the inserting end of a washing hose, a nozzle and a nozzle guide member which is freely rotatable and has the shape of a sphere of larger diameter than the outer diameter of the nozzle support body.

CONSTITUTION: When high pressure washing water is supplied to a washing hose 2, first, the washing water is injected from the 2nd ejector hole 5 and a piping washing device X advances to the interior of a pipe 1 while dragging the washing hose 2. Next, the washing water passes through a narrow passage of the nozzle support body 3 and injected from the 1st ejector hole 10 of a nozzle 8. When the washing water is injected from the 1st ejector hole 10, the nozzle guide member 14 is pushed against the inner circumferential wall 1a of the pipe 1 by injection repulsion force of the nozzle 8. Then, since the direction of the injection repulsion force of the ejector hole 10 of the nozzle 8 is more or less shifted from the center of the nozzle guide member 14, the nozzle 8 is guided to the nozzle guide member 14 while turning to move along the inner circumferential wall 1a of the pipe 1.