Plural screw holes 76 and plural through holes 77 are formed in each fixing portion 74. Each of the plural screw holes 76 and the plural through holes 77 penetrates the respective first positioning panel 72 along its plate thickness direction. The plural screw holes 76 and the plural through holes 77 are aligned in the up-down direction of the first positioning panel 72. Through holes 78 are also formed in the first back panel 71 at positions corresponding to the plural screw holes 76 and the plural through holes 77.
Each fixing portion 74 is overlaid onto a mounting face 71A for the third connectors 73 on the first back panel 71 (see