A single fuel injection is performed in either one of cylinders during fuel cut control of a diesel engine to sense torque generated with the single fuel injection based upon an increase amount of rotation speed of a crankshaft at the time. Presence/absence of abnormality in an injection start timing of an injector is determined based on a difference in torque caused when the single fuel injection is performed at multiple command injection start timings. Thus, the presence/absence of the abnormality in the injection start timing can be sensed without using a nozzle lift sensor, whereby inhibiting an increase in the number of components.