US Patent 7467627 Ignition apparatus for an internal combustion engine

An ignition coil apparatus for an internal combustion engine can prevent noise from being radiated to the outside from a transformer without requiring special man-hours even if a case takes a complex shape. The ignition apparatus is provided with a transformer (2) including a primary coil (4), a secondary coil (5) and an iron core 1, a case (3) with the transformer (2) received therein, and an insulating resin 6 filled in the case (3). A high voltage generated at a high voltage side of the secondary coil (5) upon interruption of a primary current supplied to the primary coil (4) is impressed to a spark plug (14). The case (3) is made of a conductive plastic.