PURPOSE: To prevent effectively an ignition miss by controlling additional ignition after ignition control at a definite position when an advance angle is larger than a predetermined value.

CONSTITUTION: When a calculated optimum advance angle exceeds a predetermined value, CPU1 supplies the ignition control pulse to an output interface circuit 3 on the base of said advance angle, while sending trigger pulses for generating additional energizing electric current rising from a 30° crank-shaft position α to the output interface circuit 3. As a result, the energizing current generated in a energizing circuit 6, as shown in Fig. B, will include the subsequent additional energizing current Q in addition to energizing current P at a definite position on the basis of a calculated optimum advance angle θ so that ignition is carried out twice. Thus, even if the ignition at the definite position is failured, the ignition can be ensured by the subsequent one.