Abstract: An ignition apparatus is received in a plug hole which is formed by a cylinder head and a cylinder head cover of an internal combustion engine. A side core has a slit between two horizontally extending side wall ends. The side core is selected from a laminated sheet structure comprised of two grain oriented silicon steel sheets, each having a slit between two horizontally extending side wall ends, and the plural slits align at substantially the same position. The slit prevents a one-turn short of a magnetic flux of the side core. Thereby a predetermined secondary voltage more than an engine requirement secondary voltage is obtained. An ignitor reception portion has an independent and individual ignitor reception portion and an independent and individual coil reception portion, with the ignitor reception portion and the coil reception portion being combined.

Abstract: An ignition apparatus is received in a plug hole which is formed by a cylinder head and a cylinder head cover of an internal combustion engine. A side core has a slit between two horizontally extending side wall ends. The side core is selected from a laminated sheet structure comprised of two grain oriented silicon steel sheets, each having a slit between two horizontally extending side wall ends, and the plural slits align at substantially the same position. The slit prevents a one-turn short of a magnetic flux of the side core. Thereby a predetermined secondary voltage more than an engine requirement secondary voltage is obtained. An ignitor reception portion has an independent and individual ignitor reception portion and an independent and individual coil reception portion, with the ignitor reception portion and the coil reception portion being combined.