PURPOSE: To prevent a noise generated by a water/hot water supply pipe making contact with a sheath pipe by the vibration at opening and closing a faucet by installing, to the outer circumference of the water/hot water supply pipe, a number of spacers at proper intervals in the longitudinal direction of the water/hot water supply pipe.

CONSTITUTION: After arranged between the floor slab 2 and floor board 3 of an apartment-house, a sheath pipe 1 is raised up, and arranged between a ceiling board 4 and the floor slab 5 of the upper floor, and it also vertically falls under the floor from a required position and arranged under the floor again. A water/hot water supply pipe 6 consisting of a flexible resin is inserted into the sheath pipe 1. A number of spacers are installed to the outer circumference of the water/hot water supply pipe 6 at proper intervals in the longitudinal direction of the water/hot water supply pipe 6. The water/hot water supply pipe 6 is prevented from being vibrated by the water impact accompanying the opening and closing of a faucet, and generating a sound by the contact with the sheath pipe 1.