This cable transmits high voltage to distributor, to transmit the high-voltage electricity, boosted from the ignition coil in the internal-combustion engine having portfier like gasoline engine having distributor, to the spark plug. The core that are composed of magnetic, carbon, or latex functions as the transmitter of high voltage, and EPDM-rubber or silicone insulator covering the core and the silicone coated surface consists the cable's threefold structure.. Wire wound type core was adopted in INFAC's spark plug cable, and silicone-based insulator and jacket provides high thermal resistance and high durability.