PURPOSE: To minimize a loss of power, to miniaturize the title processor, and also, to improve maintenance property by forming as one body a back panel and a bus plate, attaching its bus plate side so as to be freely attachable and detachable to a logical part printed board, and also, attaching its back panel side so as to be freely attachable and detachable to a card power source.

CONSTITUTION: Between a card power source 21 and a logical part printed board 36, that which has formed as one body a back panel 25 and a bus plate 26 is installed, and its bus plate side and its back panel side are attached so as to be attachable and detachable to a logical part printed board 36 and a card power source 21, respectively. From the card power source 21, power is supplied to the logical part printed board 36 through the back panel 25 and the bus plate 26. In such a way, a volume occupied by a bus bar for supplying the power to the printed board 36 is made small, and a loss of power can be minimized. Also, since the card power source 21 is used, the processor can be miniaturized, and also, the maintenance property can be improved.