The engine control device detects the quantity of air supplied to the engine for calculating the required fuel pressure, used for correction of the actual fuel pressure and an air/fuel ratio detector (18), coupled to a device (102) for calculating a feedback coefficient for the air/fuel ratio. The integration component of the feedback component of the air/fuel ratio is corrected when either the actual or the required fuel pressure varies, with calculation of the fuel injection quantity using the detected air quantity, the required air/fuel ratio and the feedback coefficient of the latter.
