An engine has a variable valve actuation mechanism that varies lift characteristics of an intake valve. An idle speed control apparatus has a control section for controlling an intake air amount of the engine in an idle state for adjusting an actual engine speed to a target engine speed. The control section sets a control amount related to control of the intake air amount in correspondence with the lift characteristics, which are varied by the variable valve actuation mechanism. Accordingly, the engine speed in the idle state is effectively controlled in correspondence with changes of the lift characteristics.