An exhaust gas purification system has an exhaust gas purification device (12) for purifying components in exhaust gas from an internal combustion engine (10) such as a diesel engine. In order to recover the purification ability of the exhaust gas purification device (12), and in order to prevent oil dilution occurring when post injection is conducted as part of an in-cylinder fuel injection control during an exhaust gas temperature raising control that raises the temperature of exhaust gas, the system performs the following. In a regenerative control for recovering purification ability of the exhaust gas purification device (12), injection quantities (Qp) of post injections are calculated based on previously set map data (Mp), accumulated to calculate a post injection accumulated injection amount (ΣQp), and, when the accumulated injection amount (ΣQp) exceeds a predetermined determination value (Cp), the post injection is stopped to cease the regenerative control.