A controller for controlling a fuel injection valve and a fuel pressure adjustment mechanism integrates a deposition amount of deposits per unit time, and estimates a deposition amount of deposits on an injection hole of the fuel injection valve. The controller causes the fuel pressure adjustment mechanism to increase a fuel pressure, when the estimated deposition amount exceeds a predetermined value, and corrects the unit deposition amount acquired by the deposition amount estimation according to the set fuel injection timing of the fuel injection valve. The controller corrects such that as compared with the unit deposition amount when the fuel injection timing is set to a first timing away from a top dead center of the piston by a first period, the unit deposition amount decreases when the fuel injection timing is set to a second timing away by a second period longer than the first period.