To improve an anti-
heat shock performance and an
electric field concentration relaxation (an insulation performance) between a secondary coil and a center core, to attain a narrow
diameter structure in an individual ignition type
ignition coil and further to improve an assembling working of the
ignition coil. The individual ignition type
ignition coil is adopted to an engine having a plastic head cover. A secondary coil 3 is positioned at an inner side of a primary coil 5 and between a secondary
bobbin 2 and a center core 1 a soft
epoxy resin 17 is filled up. In the secondary
bobbin 2, a secondary coil
low voltage side is a
potting side of the soft
epoxy resin 17 and an inclination having a difference in an inner
diameter is provided on the inner
diameter in which the secondary coil
low voltage side is formed large and secondary coil
high voltage side is formed small. In the secondary
bobbin, a thickness in the secondary coil
low voltage side is formed thin and a thickness in the secondary coil
high voltage side is formed thick. The soft
epoxy resin 17 has a dent 17′ according to a
compression molding and has a
glass transition point Tg which satisfies a condition of [an allowable stress of the secondary bobbin > a generation stress at (from −40° C. to a
glass transition point of an insulation resin)]. The secondary bobbin is formed by PPS and the primary bobbin is set to the primary coil at outer side of the secondary assembling body and under an assembling condition the winding is carried out.