Patent ID: 7098765

Claim:
An ignition coil comprising: a center core that is made of a magnetic material, the center core defining a magnetic passage; a primary coil that is coaxially wound on an outer circumferential side of the center core; a secondary coil that is wound coaxially with respect to the primary coil; an outer circumferential core that is coaxially arranged on an outer circumferential side of both the primary coil and the secondary coil, the outer circumferential core formed of a magnetic material, the outer circumferential core defining a magnetic passage; at least one high magnetoresistive member, each high magnetoresistive member arranged between an axially outer end portion of the center core and an axially outer end portion of the outer circumferential core on an axially same side, the high magnetoresistive member having a magnetic resistance higher than both a magnetic resistance of the center core and a magnetic resistance of the outer circumferential core; and at least one permanent magnet, each permanent magnet is located in an axially intermediate portion of the center core such that the permanent magnet is apart from an axially outer end face of the center core by a distance, which is equal to or greater than 20% of an axial length of the center core and is equal to or less than 80% of the axial length of the center core, wherein the at least one permanent magnet generates magnetic flux in a direction that is opposite to a direction, in which the primary coil generates magnetic flux.