Abstract: An internal combustion engine ignition device comprises an ignition coil, a preliminary assembly, and a casing for accommodating and covering the ignition coil and the preliminary assembly with resin. The preliminary assembly comprises a heat sink, a control unit, and a cushion cover for covering the heat sink and control unit and having at least one first protrusion. The control unit comprises a control circuit for controlling the flow of primary current in the ignition coil, and at least one first recess for engaging with the first protrusion of the cushion cover.