A control device includes: a first phase changing portion retarding a first intake valve phase relative to a second intake valve phase; a throttle valve adjusting an intake air amount of the engine, and a control portion configured to perform an intake valve phase control which controls the first phase changing portion to retard the first intake valve phase relative to the second intake valve phase such that an air amount in the cylinder of the engine is reduced to a target value to perform rich combustion, and the control portion configured to perform a throttle valve closing control which controls the throttle valve such that the air amount in the cylinder is the target value or smaller after the air amount in the cylinder is not reduced to the target value or smaller by the intake valve phase control performed by the first phase changing portion.