WATERPROOF PAN FOR BATHTUB

PROBLEM TO BE SOLVED: To provide a waterproof pan for a bathtub, capable of covering the periphery of the bathtub to the upper end thereof even in a narrow bathroom.SOLUTION: A waterproof pan for a bathtub, which is installed adjacent to a washing place and has a rectangular shape in a plan view, is container structured to have a bottom surface and side walls and capable of accommodating the bathtub inside the container, with the upper end of the side walls being capable of coming into close contact with the outer surface of the accommodated bathtub. The container has: the bottom surface; a main part in which the side walls on one short side of the bathtub and the side walls on a long side opposite to the washing place are integrally formed; and a division part forming at least a part of the side walls on the other short side of the bathtub. The division part is assembled to the main part.