In the case of the second module fastening hole MH2 and the third module fastening hole MH3 placed near the second short side SS2 on which the memory connector MCN is not located, although the distance spaced from the second short side SS2 in the first direction X may be the same, by designing the spaced distance of the second module fastening hole MH2 to be greater than the spaced distance of the third module fastening hole MH3, it is also possible to alleviate a spaced distance deviation in the first direction X between the module fastening holes MH1 to MH4. In this case, the straight line which connects the second module fastening hole MH2 and the third module fastening hole MH3 may be inclined at a second angle θ2 with respect to the second direction Y. The second angle θ2 may have the same sign as the first angle θ1. The second angle θ2 may have a smaller absolute value than the first angle θ1, but is not limited thereto. In an embodiment, the figure obtained by connecting each of the module fastening holes MH1 to MH4 may define a trapezoid.