An exhaust gas purification system with which diesel particulate filter (“DPF”) regeneration can be continued even when deceleration occurs during the DPF regeneration. The system includes a regeneration deceleration period intake/exhaust control unit that, when a vehicle decelerates during the DPF regeneration, increases an exhaust gas flow rate through an exhaust pipe by controlling respective openings of an exhaust gas recirculation (“EGR”) device and an intake throttle and adjusting a turbocharging amount of a high pressure stage turbocharger.