Provided is an exhaust gas purification system that can prevent adhesion of urea water in a dosing valve during DPF regeneration. An exhaust gas purification system 100 includes a DCU 126 that controls a supply module 106 to inject or return urea water inside a dosing valve 104 to a urea tank 105 in order to remove urea water accumulated in the dosing valve 104 when receiving a DPF regeneration authorization request from an ECM 125, and then transmits a DPF regeneration authorization to the ECM 125 when determining that an NH3 amount of an SCR catalyst is less than or equal to a prescribed value.