PURPOSE: To carry out securely leaning in idling for stable idling by providing individually idle learning correction values independently from a learning map and stopping feedback correction when the learning of idle learning correction value is performed by a predetermined number of times.

CONSTITUTION: To a control unit 20 are input detecting values of an air flow meter 6, O2 sensor 13, throttle sensor 14, idle switch 15, water temperature sensor 16, crank angle sensor 17, neutral switch 18, etc., to controllably calculate the opening time of a fuel injection valve 19. The control unit 20 performs learning under the steady running condition after the completion of warming-up in every region corresponding to basic fuel injection amount and rotational frequency on the basis of the peak value of air fuel ratio correction factor. The control unit 20 performs the learning by set number of times in idling with respect to idle learning correction values stored independently from a learning map on the base of the peak value of feed-back correction factor and then stops the feedback correction.