Rotation recognition means for recognizing a revolution of a crankshaft based on the cylinders before the combustion cycle of a cylinder in question is provided. When the supply of fuel by injection from an injector to a certain cylinder of the six cylinders has become impossible, then control is performed to change the number of cylinders targeted by the rotation recognition means so as to recognize the revolution of the crankshaft for all six cylinders whose combustion cycles are consecutive prior to the combustion cycle of the cylinder in question, and to stop the supply of fuel from the injectors for supplying fuel to cylinders whose combustion cycles are equally spaced from the cylinder to which the supply of fuel is not possible, so that the spacing between the combustion cycles in the cylinders whose combustion cycles come before and after and sandwich the cylinder to which the supply of fuel is not possible becomes uniform.