IGNITION TIMING CONTROL DEVICE OF ENGINE

PURPOSE:To suppress an influence of fluctuation in an angular speed of a camshaft by using a riseup or falldown of a square wave signal by a crank angle sensor to serve as a trigger to perform hard ignition at starting time, and setting ignition timing based on a signal output by a peak of a rotational period of the camshaft. CONSTITUTION:In an ignition timing control device for controlling ignition timing based on an output signal of a crank angle sensor 31, the crank angle sensor 31 is constituted such that a riseup or falldown of a square wave signal is output in the vicinity of the signal containing the top dead center reversely to output the falldown or riseup of the square wave signal in an almost peak of a rotational period of a camshaft. When a starting operational condition is decided with a starter switch in an on-condition further with an engine speed in a predetermined value or less, hard ignition is executed based on the riseup or falldown of the above-mentioned square wave signal, and on the other hand, in an ordinary operational condition except at starting time, the ignition timing is set based on the riseup or falldown of the square wave signal output in almost the peak in the rotational period of the camshaft.