An ignition coil for an internal combustion engine includes a wire-wound resistor. The wire-wound resistor includes a core material, a conductor winding, a pair of metal caps disposed at both ends of the core material, the pair of metal caps in contact with the conductor winding, and a resin coating material disposed so as to be in close contact with the core material and the conductor winding. The resin coating material is filled between the conductive winding and the resin coating material is formed to cover the conductor winding from an outer peripheral side of the conductor winding The metal cap includes a bottom portion and a cylindrical side portion. An inner peripheral side of the side portion is provide with ridges projecting internally formed along a direction crossing a winding direction of the conductor winding.