To enable a case unit to be stacked on another or many others to use them in a proper condition, by equipping a stepwise fitting part on the upper end part of the case frame to enable the bottom plate of the case unit to fit into the fitting part of another case unit.

This case unit A comprises a case frame 1 and a bottom plate 11 integrally. The case frame 1 is formed so as to be surrounded by side plates 2, 3 and a back plate 4, and the front face is opened. On the upper end part 6 of the case frame 1, an inward directed stepwise fitting part 7 is equipped. On the step part 12 of the bottom plate 11, a lower end part 8 of the case frame 1 is equipped to compose the case frame 1 integrally upward from the bottom plate 11. Thus, since the bottom plate 11 of the case unit A is stacked on a fitting part 7 on another case unit A, the case unit A can be stacked on another or many others.