To provide a drop basin composed of a drainage basin having a three-layer structure and capable of effectively utilizing scrap caused when injection-molding or extrusion-molding a resin molded object and an old used waste material.

This drop basin is composed of the drainage basin 1 in which an upper part of a cylindrical basin main body 11 is opened, an invert 12 is formed in a lower part of the basin main body 11, and a connection part 13 of a flow-out pipe 3 is formed in a lower part of a side wall of the basin main body 11 by communicating with the invert 12 and a pipe 2 for inspection and cleaning port connected with an opening part at an upper end of the drainage basin 1 and rising up to a position close to the ground surface. It is connected with a branched joint 4 for connecting a flow-in pipe 5 with an outer face of a side wall of the drainage basin 1 or an outer face of a side wall of the pipe 2 for inspection and cleaning port. An intermediate layer 1a of the basin main body 11 is formed by a resin raw material containing a reproduced raw material formed by crushing scrap of the resin molded object and the waste material. Inner and outer faces of the intermediate layer are covered with an inner layer and an outer layer formed by an unused resin material containing no reproduced raw material.