A bus bar module includes an electric wire routing structure that is attached to an battery assembly including a plurality of battery cells and accommodates a plurality of bus bars in which each electrodes of the battery cells is electrically connected to each other, a plurality of electric wires connected to the battery cells via the bus bars, respectively, an electric wire routing groove formedin the electric wire routing structure and accommodating the electric wires in a pair of side walls, and a lid that is supported by a first side wall via a hinge and covers the electric wire routing groove to block a groove opening.