PURPOSE: To simplify the handling of electronic parts or electric wiring and to protect a control circuit by a method wherein a control panel is received in a base body in a state bonded along with a shield plate and a lid body is bonded to the base body in such a state that respective connectors and the key insertion port of a mode setting switch are exposed to the outside of the lid body.

CONSTITUTION: The control panel receiving box on the rear side of a rear cover 2 is divided into the base body 8 formed from a transparent synthetic resin material and bonded to the rear cover 2 in a vertical state in a releasable manner and the lid body 9 formed from a transparent synthetic resin material and arranged on the rear side of the base body 8 to be bonded to the base body 8 in a separable manner. The conductive shield plate 32 shielding the front side surface of a control panel 18 is closely fitted in the base body 8 along with the control panel 18. The switch insertion hole 37 through which the rear part of a mode setting switch 19 pierces is provided to the back plate 9a of the lid body 9. Further, the lid body 9 is bonded to the base body 8 in a releasable manner in such a state that the connectors 21 and fuses 22 for respective substrates are exposed to the outside.