PURPOSE: To enable a stable advance control to be carried out in a range below the idling speed of an engine so as to surely prevent the engine stall at the time of rapid deceleration.

CONSTITUTION: A plurality of reluctors r0, r1 are provided at a rotor of a signal generator synchronously rotating with an internal combustion engine, and with these reluctors magnetic flux change is generated in a signal generation element 202 to generate a control signal Vp. The circular arc length of the specified reluctor r1 is made longer than that of the reluctor r0, and with the difference between these lengths a relation between each control signal generated from the element 202 and the rotation angle of engine is specified. At the time of start-up of internal combustion engine, an ignition signal is generated with the control signal generated at the rear end of the reluctor r0, while the ignition signal is generated with the control signal generated at the front end of the reluctor r0 when the engine speed is over the start-up speed and below the idling speed.