Abstract: An X-ray cassette for retaining an X-ray sheet film or the like. The frame (13) of the X-ray cassette comprises corner members (20) corresponding to corner portions of a front plate and straight members (30), connected to the corner members and corresponding to side portions of the front plate. The corner members (20) each have a nearly L-shaped body (21), fitting projections (22) protruding from both ends of the body (21) and fitting pins (23) formed integrally. The straight members (30) have each fitting recesses (31, 32) to receive the fitting projections (22) and fitting pins (23) of the corner member (20), with front-plate receiving grooves (24, 33) formed continuous in the inner walls of the corner members (20) and straight members (30) for receiving edge portions of the front plate (12). Accordingly, it is possible to reduce the manufacturing cost of the X-ray cassette and improve the strength thereof.