An exhaust gas purification system includes a previous-stage oxidation catalyst device, an ammonia-based solution feeder, a Diesel Particulate Filter (DPF) device, a turbine of a turbocharger, and a NOx selective reduction catalyst device in the exhaust system of an internal combustion engine in this order from an exhaust port side. The NH3 production rate is improved, thereby improving the NOx removal rate; the temperature of the DPF device is kept high to increase the time and frequency of continuous regeneration, thus decreasing the frequency of forced regeneration of the DPF device and the amount of discharge of CO2 produced during the forced regeneration; and also corrosion of the turbine of the turbocharger by SOx is suppressed.