To adopt such a constitution that a bus bar wiring board 13 and a printed board 15 are electrically connected with each other, and obviate complicated soldering operation and new electrical components.

Female-female-type junction terminals 17 are installed on the tab terminals 12a of bus bars 12 installed at edges of a bus bar wiring plate 13. The junction terminals 17 are connected by fuses 8 with junction terminals 18 on a printed board 8 installed opposite to the junction terminals 17. As compared with conventional methods wherein the tab terminals of bus bars are soldered to printed wiring on a printed board, the above method obviates this soldering and facilitates electrical connection between a bus bar wiring plate 13 and a printed board 15. With this method, assembling work is facilitated and cost is reduced. Addition of new electrical components is unnecessary and the circuitry is significantly simplified.