PURPOSE: To reliably stop ignition without requiring a special thyristor for shortcircuiting an armature, by conducting an ignition switching element continuously even after igniting operation by means of a stop signal fed from a stop switch.

CONSTITUTION: When a high level step signal E is inputted from a normal close operating switch, i.e. a stop switch 24, to the input port I2 of a microcomputer 22, an ignition signal being outputted at next ignition time is maintained at high level. Although a capacitor 7 is discharged instantaneously when said ignition signal is outputted so s to carry out ignition, a thyristor 8 is maintained in conductive condition. Consequently, the capacitor 7 is shortcircuited by an ignition coil 9 and the opposite ends of an armature coil 3 are kept in a condition shortcircuited by the thyristor 8. Consequently, the capacitor 7 can not be charged irrespective of the rotation of a magnet rotor 1, and the ignition is stopped reliably thereafter.