u03b4t is a positive figure is referring to the equations 1 7 39 and 8 equ11 the condition in which the inequality 9 is satisfied with reference to the ignition lead angle u03b8 is the energizing start time is computed within a range of ignition timing satisfying the inequality 10 by the energizing start time calculator means 23 and more particularly obtained from equ12 within the ignition timing satisfying the inequality 10 the energizing start time is defined by both the period of engine revolution and the energizing time tl for the ignition coil 42 while not depending on the ignition period as apparent from the equation 4 39 fig2 illustrates the operation of this embodiment during acceleration the energizing start time advances u03b4t fig2 c thus to ensure a sufficient length of energizing time with the ignition control signal ps even if the ignition is turned on by the signal psd fig2 f when the ignition lead angle u03b8 is zero due to the advanced energizing start time the energizing time deficiency u03b4t is 0 7 ms from the equation 8 in the condition that the engine speed increases in number of engine rotation 100 rpm per one ignition cycle under the engine speed at about 1000 rpm however the energizing is advanced in timing by advancing action as represented by the equation 4 39 and as the result no energizing time deficiency will be created during continuous running.