To improve responsiveness of idle rotational speed control by changing at least one timing of the opening timing and closing timing of intake/exhaust valves according to the load condition of an engine at the time of idle operation, in a device in which opening/closing control of the intake/exhaust valves is carried out by an electromagnetic actuator.

During operation of a vehicle, it is judged by the idle condition judging unit 76 of an ECU 56 whether an engine operating condition is during idle operation or not, real engine speed is detected from the detecting signal of a crank angle sensor 50 when 'YES' is judged, and it is stored in a RAM temporarily. A target idle rotational speed is calculated from a compressor switch sensor 51, a water temperature sensor 52, and a torque converter load signal detecting sensor 53 in a target idle rotational speed calculating unit 78, the target idle rotational speed is compared with real engine speed, and a rotational sped difference is calculated in a rotational speed difference comparing and judging unit 80. The controlled variable of an actuator 44 is calculated by an actuator controlled variable calculating unit 82, a control signal c is outputted, and an intake valve and an exhaust valve are opening/closing controlled.