A busbar module includes: a circuit body having a flexible circuit board; busbars; and a holder. The circuit body has: conductor layers and protective layers to form a multiple-layered structure of wiring patterns; a band-shaped main strip to be located to extend in a stacking direction of cells; and a band-shaped branch strip branched from the main strip. The branch strip has: a bent portion extending in the stacking direction and having a bent shape around an axis crossing the stacking direction; and a connection portion disposed closer to an end of the branch strip than the bent portion and connected to the corresponding busbar. The bent portion has a thin-layer portion having a shape formed by removing, from the flexible circuit board, a part of the protective layers corresponding to a part of the conductor layers without being used as the wiring pattern in the branch strip.