To improve engine operability during idle operation.

When the load of a power steering pump serving as an accessary is applied during idle operation, based on a correction air amount being a fundamental value equivalent to the load of a power steering pump, correction is effected through high response F/F control, such as an ignition timing and a fuel injection amount. Simultaneously therewith, based on a negative pressure correction factor B computed from a value QHO equivalent to an intake negative pressure, an equivalent ratio and a correction factor (1-×B) to effect correction of a negative pressure are calculated. By multiplying the correction factor (1-×B), an air amount equivalent to the load of a power steering pump selecting a high value from the fundamental value and a correction air amount, a correction air amount is calculated. By controlling an electronic control type on-off valve and/or a throttle valve located in a bypass passage bypassing a throttle valve based on a correction air amount, low response F/F control is carried out.