A plurality of sets of power storage devices each formed by connecting a plurality of power storage devices in parallel are connected in series. A wiring module that is arranged on a plurality of power storage devices each having electrode terminals, the wiring module including: a plurality of connection bus bars each connected to a corresponding electrode terminal and each having 2n (n is a natural number greater than or equal to 2) electrode connection portions; and an insulating protector that houses the plurality of connection bus bars. In each of the plurality of connection bus bars, the cross-sectional areas of the second electrode connection portion from the right of the connection bus bar and the third electrode connection portion from the right of the connection bus bar are set to be larger than the cross-sectional areas of the other electrode connection portions.