A controller for an internal combustion engine includes a controlling section that controls a variable valve actuation device such that the phase of an intake valve becomes a target value. The controlling section executes a process of setting the target value to a steady or transient state phase, a process of calculating a load change rate, and a process of setting a change amount of the transient state phase. The change amount of the transient state phase is set to a change amount when the engine operating state is a transient state and the load change rate is greater than or equal to a predetermined threshold. The change amount of the transient state phase is set to a second change amount that is less than the first change amount when the engine operating state is the transient state and the load change rate is less than the threshold.