PURPOSE: To activate catalyst for purifying exhaust gas early without worsening running property after an engine is started in cold condition and make the early activation of the catalyst compatible with the improvement of warming up performance.

CONSTITUTION: When an engine is in the steady operation condition after it is started in the cold condition, the basic coefficient KHC is used as the basic value KHC1 (S331), and then compensation is done in such a way that lag angle amount is increased with the temperature rise of cooling water. Also, when the engine is in the acceleration operation condition, the basic retard coefficient KHC is set on the lead angle side as the retard coefficient initial value KHCO at the time of acceleration (S330), and the value is added to the basic retard coefficient KHC by every compensation value KHCA per the number of set ignition times (NKHC2) (S336) to increase it gradually on the lag angle side. Consequently, catalyst is activated early, exhaust gas emission is improved, and warming up performance is improved. Further, it is possible to prevent a running property from worsening at the time of acceleration operation.