Disclosed is an exhaust gas recirculation system provided in an engine to recirculate, to an intake manifold, a part of exhaust gas discharged from an engine body, as EGR gas. The exhaust gas recirculation system comprises: an in-head gas passage formed in a cylinder head to allow the EGR gas to pass through a position adjacent to a first coolant jacket formed in the cylinder head to allow coolant to flow therethrough an EGR cooler configured to cool the EGR gas after passing through the cylinder head via the in-head gas passage and before being introduced into the intake manifold; and a relay pipe configured to guide the EGR gas just after passing through the cylinder head, to the EGR cooler. The relay pipe is provided with a second coolant jacket for allowing coolant to flow therethrough so as to cool the EGR gas being flowing inside the relay pipe.