To maintain both warming up performance of a catalyst and stability of idle rotation while reducing exhaust emissions during catalyst warming up control for warming up the catalyst by delaying the ignition timing of an engine.

In this control device, when the opening of an ISC valve 35 (idle rotation control valve) becomes larger than a predetermined value A during the catalyst warming up control and a required intake air volume (intake air volume required for preventing idle instability) approaches the upper limit within a range of intake air volume adjustable by the ISC valve 35, the opening of a TCV 33 (tumble control valve) is corrected to an opening-side after the amount of ignition timing delay is corrected to be reduced and the opening of the ISC valve 35 is corrected to be reduced. Meanwhile, when the opening of the ISC valve 35 becomes smaller than a predetermined value B and the required intake air volume becomes sufficiently smaller than the upper limit within the range of the intake air volume adjustable by the ISC valve 35, the amount of ignition timing delay is corrected to be increased and the opening of the ISC valve 35 is corrected to be increased, after the opening of the TCV 33 is corrected to a closing-side.