To facilitate attachment and detachment of an equipment body.

Each of lateral fitting side plates 9d has a guide groove 21 formed having a cutout of first specified dimensions in a horizontal direction so that a machine screw 23 screwed into each of lateral side faces of an equipment body can be engaged with the cutout, and a guide groove 22 formed having a cutout of second specified dimensions longer by the specified dimension in the horizontal direction so that a machine screw 24 screwed into each of lateral side faces of the equipment body can be engaged with the cutout. In the installed state of the equipment body with the machine screw 24 engaged with the cutout of the guide groove 22, the machine screw 23 is engaged with the cutout of the guide groove 21 so as to be detachable, thus making the equipment body attachable to and detachable from the lateral fitting plates from below.