To prevent flameout at the time of discharging NOx from an NOx absorbent in a stratified combustion type internal combustion engine.

An air-fuel mixture is stratified in a state where an average air-fuel ratio is lean at the time of engine low load driving, and NOx generated at this time is absorbed by the NOx absorbent 26 arranged in an exhaust passage. The average air-fuel ratio is changed from lean to rich at the time of making the average air-fuel ratio rich to discharge NOx from the NOx absorbent 26, and a degree of stratification at this time is lowered.