In a variable valve timing apparatus in which a phase of an intake valve
is changed at an amount of change according to a rotational speed of
relative rotation between an electric motor as an actuator and a
camshaft, the set upper limit value of the rotational speed of relative
rotation and a coefficient N.theta. of conversion from a required
phase-change amount to the rotational speed of relative rotation
.DELTA.Nm in each control period are set at smaller values at the time of
engine stop than at the time of engine operation. As a result, the
rotational speed of the electric motor in the VVT operation at the time
of engine stop is reduced thereby reducing the operation sound of the
variable valve timing apparatus.