To facilitate maintenance by fitting an upside cover, which is bonded with a downside cover while overlaying an upside shield case, with the upside of a front panel.

A substrate 60, radiator sheet 70 and copper plate 80 are attached to a frame 50 by a substrate attaching screw 81. Next, a front panel 20 is attached to the frame 50 by a front side attaching screw 24, a rear panel 30 is attached to the frame 50 by a rear side knob screw 31. Next, a front side cable 61 is connected to an imaging device (CCD) 21, and a rear side cable 61 is connected to a connector provided on the rear panel 30. Next, the frame 50 is arranged on a downside cover 40. In this case, the frame 50 is arranged at a recessed frame passing part 44, the rear side cable 61 is arranged at a recessed rear side cable passing part 45, and the substrate 60 is dropped into a recessed side face shielding part 46. Then, an upside cover 10 and a downside cover 40 are bonded, and the upside cover 10 and the downside cover 40 are fixedly assembled by an upside knob screw 11.