PURPOSE: To rationalize and simplify construction and perform stable supply of hot water and water by providing a duplex tube, applied mainly in a house, with a hot water feed duct and a water feed duct disposed parallel therein, and further providing an information line at the adjacent part of these ducts.

CONSTITUTION: Inside a pair tube 1, a duplex tube with plural built-in ducts, a hot water feed tube 1a for feeding hot water and a water feed tube 1b for feeding water to each terminal part are disposed parallel. An information line 1c for supplying each information is further provided parallel at the adjacent part between the hot water feed tube 1a and the water feed tube 1b. The pair tube 1 is formed of deflectable material such as synthetic resin and disposed in the loop state inside a house at the time of construction. Because of using the deflectable pair tube 1, piping can be rationalized, and elbows can be omitted. Also, because of loop disposition, water pressure is prevented from running down even if faucets or the like are used simultaneously at plural terminal parts, thus enabling stable supply of hot water and water.