To solve such a problem that an injection rate is varied by a variation in common rail pressure during injection from an injector, particularly, the the injection timing of the injector may be overlapped or not overlapped with the pumping timing of a supply pump when the pumping timing is asynchronous with the injection timing of the injector, resulting in a large variation in actual injection rate by the variation in common rail pressure.

The common rail pressure during the valve opening of the injector 3 is always monitored, a predicted injection rate QEST equivalent to an injection rate injected from the injector 3 is provided by starting the integration of the common rail pressure from the start of injection of the injector 3, and the injector 3 is closed when the predicted injection rate QEST reaches an instructive injection rate QFIN. Thus, a variation in instructive injection rate QFIN provided by an ECT 5 and an actual injection rate injected from the injector 3 can be suppressed even if the common rail pressure is varied during injection when the pumping timing of the supply pump 4 is asynchronous with the injection timing of the injector 3.