BUSBAR MODULE

A busbar module (1) includes: a plurality of busbars (2) arranged along a first direction (X) and connected to battery cells; and a plate-like circuit body (3) having a plurality of detection lines (71) to be connected to the busbars and having flexibility, in which the circuit body includes a main line portion (30) in which the plurality of detection lines is routed and branch portions (31), branching from the main line portion and in which the detection lines to be connected to the busbars are routed, the branch portions each include a stretchable portion (34) that is stretchable along the first direction, the stretchable portions each have slits (34a and 34b) or a cutout formed in a direction intersecting the first direction in a plan view of the circuit body, and a detection line of each of the stretchable portions is routed along the slits or the cutout.