A plurality of double-sided circuit boards 1 in which a circuit 4 is provided on either side of an insulating layer 3 comprising an organic high molecular resin with an alloy foil 2 as a basic substance, and two circuits 4 are electrically connected by a via with a soldered conductor 5a filled therein are laminated via an adhesive layer 6. The adhesive layer 6 has a bore opened at a predetermined position of a portion in direct contact with the circuits 4 of two double-sided circuit boards 1. A bore portion is provided with a soldered conductor 7. The circuits 4 of the two double-sided circuit boards 1 are electrically connected by the soldered conductor 7.