To prevent an abrasion, a damage or the like due to the repeated insertion and extraction of the high-pressure water nozzle of an extension pipe in which a branch pipe with a clean-out is implanted in a side face.

In a drain trap with the clean-out for a disposer, a rubber bush with a cylindrical section, in which an outer wall surface is stuck fact to the branch pipe and the extension pipe, and both-end collar sections is inserted and stuck fast to the branch pipe section of the extension pipe extensively over a connecting section to the extension pipe through the inner wall of the branch pipe from the clean-out for the extension pipe in which the branch pipe with the clean-out is implanted in the side face, and the connecting section of the branch pipe and the extension pipe is covered particularly. A splash guard composed of a film with a chrysanthemum-shaped notch is lined on an inner wall in the vicinity of the clean-out for the rubber bush.