A method for manufacturing busbar modules that includes placing a plurality of first linear conductors on one side and a plurality of second linear conductors on the other side across a long planar conductor, extruding an insulating cover material to cover the first linear conductors and join the first linear conductors to the planar conductor with the insulating cover material and to cover the second linear conductors and join the second linear conductors to the planar conductor with the insulating cover material, cutting the planar conductor along first, second and third cutting lines, forming a first busbar module by joining the first linear conductors and the plurality of busbars, and forming a second busbar module by joining the second linear conductors and the plurality of busbars.