To provide confluence inlets capable of easily connecting inlets to outlets having watertight joints.

Catch basins 2a, 2b and 2c are provided by connecting inlets 4a, 4b and 4c and outlets 5a, 5b and 5c each other through invert portions 3a, 3b and 3c. Branch pipe inlets 15a, 15b, 15c and 15d are protruded at the side portions of the catch basins 2a, 2b and 2c. The inlets 4b and 4c of the catch basins 2b and 2c and the outlets 5a and 5b of the catch basins 2a and 2b are connected together through packing 14. The inlets 4b and 4c of the catch basins 2b and 2c and the outlets 5a and 5b of the catch basin 2a and 2b can be connected accurately and strongly. And the portion between the inlets 4b and 4c and the outlets 5a and 5b can be easily connected together in a watertight state.