PURPOSE:To obtain a retard angle characteristic having fixed slope for ignition timing, by subtracting a fixed time from a fixed crank angle. CONSTITUTION:Electric charge is performed at a constant current I2 from the point when a reference position pulse B is generated, then electric discharge is performed at a constant current I1 from the point when charging voltage becomes V2. An ignition pulse is output at the point when discharge voltage becomes V3. An angle alpha is a fixed angle without relation to rotary speed. An angle gamma is a fixed time without relation to rotary speed. Accordingly, a retard angle beta is retarded with a rise of rotary speed at constant slope. While the second reference position pulse output at the other reference angle may be used to obtain a constant retard angle characteristic. The retard angle characteristic with constant slope can be obtained from the first reference position pulse and the constant retard angle characteristic can be obtained from the second reference position pulse. In this way, the respective characteristic can be optionally set independently.