To make effective use of an injector with no highly precise injection property, if used for an engine in which no air/fuel ratio feedback control is performed, by restricting the deviation or dispersion of an air/fuel ratio.

An electronic control unit(ECU) 30 individually calculates a controlled variable for each injector 7 as a property controlled variable when an engine speed detected corresponding to each of cylinders #1, #2 by an crank angle sensor 22 during idling operation after warm-up is a reference engine speed and individually calculates and stores the ratio of each property controlled variable to a reference controlled variable as a property corrected value for each of the cylinders #1, #2. The ECU then corrects the controlled variable equivalent to the injection amount of one injector 7 to inject fuel every time for each of the cylinders #1, #2 in accordance with the property corrected value and controls the corresponding injector 7 in accordance with the corrected controlled variable.