To provide a plate joint structure of a dishwasher wherein corrosion in gap is prevented even when a seal material is not used and manufacturing costs are reduced, and which has excellent manufacturing efficiency.

The plate joint structure of a dishwasher includes one plate such as one side plate 311 of a casing 3 and the other plate such as the top plate 32 of the casing 3. On a part of the end face of the outer edge of the one plate, the inner side surface of the outer edge of the other plate abuts. Then, the outer edge of the other plate is melted in from the side of the outer side surface by laser welding, thereby welding the outer edge of the other plate and the outer edge of the one plate. It is preferable that a weld bead 35 made by melting of welding is formed at an inner portion of a welded place.