The present invention is intended to provide an enhanced conductor module capable of reducing a joint area between conductors, and a method for preparing the same. The conductor module has a pair of flattened circuits each of which comprises a rectangular shaped conductors, a pair of sheeted coverings disposed on both sides of the conductor, and at least one hole having a diameter smaller than a width of the conductor, and formed in the coverings so as to expose one surface of the conductor to outside the flattened circuit. The conductor of one flattened circuit is joined to the conductor of the other flattened circuit via the hole by application of electromagnetic welding.