By providing an EGR system with an exhaust gas recirculation line (G4) that recirculates a portion of the exhaust gas discharged from an engine body (11) to the engine body (11) as a portion of gas for combustion, an EGR inlet valve (41) that is provided in the exhaust gas recirculation line (G4), and a purge gas supply line (G11) that serves as a purging device that supplies a purge gas to the exhaust gas recirculation line (G4) and discharges a remaining corrosive component, piping corrosion is prevented by removing the corrosive component that remains in the exhaust gas recirculation line.
