To well maintain engine stability, exhaust performance, etc., even by performing a retard of ignition timing for early activation of a catalyst.

At retard time of ignition timing (judge in S14) for early activation of an exhaust emission purifying catalyst 8, and a fuel increase correction amount KFR is calculated (S15), based on a basic value [basic increase factor (%)] set in accordance with an engine water temperature Tw and a correction value (1-AVPB/PB) of change degree of an intake pressure PB. By calculating the last fuel injection amount Ti (S16) based on this KFR, fuel can be supplied to well follow a change of wall flow (air/fuel ratio), even when it is provided, generated by a change of load due to a retard of ignition timing. In this way, air/fuel ratio can be well controlled to the target even by performing a retard of ignition timing for early activation of a catalyst. Accordingly engine stability can be well maintained, and also even fuel consumption, exhaust performance, etc., can be improved.