A multicore cable includes a plurality of cables in parallel and is formed by fusion-welding the plurality of cables with a resin jacket. Each of the plurality of cables is formed by winding a shield around a signaling core wire, which is covered with an insulating material, and a grounding core wire. The resin jacket and the shield are stripped so that a stair portion is formed. The stair portion is coated with an electrically conductive adhesive. A vibration is exerted on the grounding core wire, thereby connecting the shield with the grounding core wire with the electrically conductive adhesive. Eventually, the shield and the grounding core wire are bonded with the electrically conductive adhesive. This allows an electrical connection between the shield and the grounding core wire to be maintained in a desirable condition, thus making it possible to suppress a characteristic impedance variation of the signaling core wire caused by an external factor.