To contrive not to require great strength when a lid mounted on a sliding surface arranged at a frame member is to be slid and further improve its durability by a method wherein an opening edge of a show case comprised of an inner case and an outer case is provided with the frame member in a stepwise manner from the outer case toward the inner case and then its horizontal plane is formed at a corrugated sliding surface.

A freezer show case has an outer case 1 with an upper part forming an outer appearance of the case being opened, an inner case 2 having its upper part opened, a thermal insulator 3 arranged between the inner case 2 and the outer case 1, and a frame member 4 connecting the upper ends of the outer case 1 and the inner case 2 in a thermal insulating manner and then an upper opening part of the freezer show case is provided with a sliding type lid. In this case, the frame member 4 is formed to be in a stepwise manner descending from the outer case 1 toward the inner case 2, wherein each of the horizontal planes of the upper-most stage and an intermediate stage of the frame member 4 is applied as a sliding surface 68 where each of the upper and lower lids 5a, 5b is slid and the surface of each of the sliding surfaces 68 is formed with a corrugation. With such an arrangement as above, a person does not require a great strength for opening or closing the lids, and to cause a scar to be hardly made at the frame member 4.