To provide a drainage, basin having a branch pipe coupling, to widely adjust the connection direction and the angle of a pipe to be connected, such as an inflow pipe, and prevent the occurrence of a leak accident of pipe fluid at a coupling even when an earth pressure and a wheel load are exerted on a coupling buried in a ground and a ground fluctuation occurs due to an earthquake.

One end of a coupling 6 made of rubber is connected to a cylinder body 54 surrounding a through-hole 11, formed in the side wall 1 of a pit body, and the outer peripheral side of the coupling 6 made of rubber is covered with a cylindrical hood 55. Further, a socket 541 in which the end part of a pipe 3 to be connected is inserted is arranged at a cylinder body 54, and a stopper step part 542 is formed only at the upper part of the inner periphery on the deep side thereof.