An object is to enable an exhaust gas purification system to bring about satisfactory oxidation of fuel in an oxidation catalyst in a temperature raising process of a filter, thereby allowing fuel supply to be performed at as low a temperature as possible. In the exhaust gas purification system, when the temperature of the exhaust gas flowing into the oxidation catalyst exceeds a specific threshold temperature that is determined based on the cetane number of fuel, a controller performs the temperature raising process. If the quantity of heat generated in the oxidation catalyst per unit time is smaller than a specific value while the temperature raising process is being performed, the temperature raising process in progress is suspended. The temperature raising process is resumed later on when the temperature of the exhaust gas flowing into the oxidation catalyst exceeds an updated threshold temperature higher than the specific threshold temperature.