Each terminal electrode has a welded portion at which each end portion of a conducting wire is electrically connected to each terminal electrode upon laser welding. The conducting wire is provided with an insulation coating. The insulation layer has an edge on the surface of the conducting wire. Each welded portion has a bulge portion bulging in a direction away from the core and in contact with only the edge of the insulation coating. The edge determines a shape position and size of a melted bulge portion.