A refill case that includes a middle plate, the middle plate has a bottomed short cylinder shape that contains a cosmetic item and an outward brim along the periphery, a case body that accepts and keeps the middle plate, and a cap that is fitted around the case body detachably in screw engagement. The refill case also includes a ring-shaped gasket made of a soft, elastic material used to seal the middle plate through tight contact of the brim, and a butting wall disposed on either one of the case body or the cap to butt against the other one at a position in which screw engagement of the cap is complete and in which soft contact deformation of the gasket is controlled within a range of elastic deformation. The gasket is fitted to the cap in an undetachable manner but having play relative to the roof.