PURPOSE: To perform the wiring works effectively without requiring the size of harness main line or the wiring regardless of whether the automobile concerned is of right-hand or left-hand drive type.

CONSTITUTION: The first fuse box 72 is installed on the steering wheel 70 side while the second fuse box 74 is installed on the side opposite the steering wheel 70 and a relay box 34 is installed in the first mounting part 36 of the right side part 32a in the case of an automobile of left-hand drive type and in the second mounting part 38 of the left side part in the case of an automobile of right-hand drive type. Thus the wirings are configured symmetrically in the left-hand and the right-hand drive car.