An engine comprising: a fuel injection device including a rack and an actuator, the rack being configured to regulate the amount of fuel injected to a combustion chamber, the actuator being configured to control the position of the rack; and a control device that controls fuel injection performed by the fuel injection device based on an instructed revolution number, and that performs a dither control on the actuator, wherein the control device has information of a revolution number variation region that is based on the relationship between a dither frequency in the dither control and an engine revolution number, and upon determining that the instructed revolution number is within the revolution number variation region, changes at least one of the dither frequency and the instructed revolution number. Thus, an engine capable of reducing a periodic variation in engine speed which may be caused by a dither control is provided.