Ignition device for an internal combustion engine and its assembling method

摘要

An insulator includes a plug side cylindrical portion having an inner space for accommodating a center electrode and a coil side cylindrical portion extending in a direction departing from a combustion chamber. The high-voltage portion of an ignition coil is entirely accommodated inside the coil side cylindrical portion. According to this arrangement, the coil side cylindrical portion can assure insulation between the high-voltage portion and the low-voltage portion. The portion to be insulated and fixed by an insulating resin is limited only to the secondary winding.