An engine comprising an exhaust gas recirculation system, the engine comprising: an engine body including: a combustion chamber in which combustion is performed; and a cylinder head provided in an upper part of the engine body and having a water-cooling passage through which cooling water can flow; an intake passage connected to the cylinder head and through which intake air can be introduced into the combustion chamber; an exhaust passage connected to the cylinder head and through which exhaust gas can be discharged from the combustion chamber; and an EGR passage connecting the exhaust passage to the intake passage and configured to recirculate the exhaust gas as EGR gas, from the exhaust passage to the intake passage, the EGR passage including: an EGR cooler configured to cool the EGR gas; and an EGR internal passage constituting the EGR passage upstream of the EGR cooler, and including a passage passing through the cylinder head, wherein the EGR internal passage has a bent pipe part and the water-cooling passage is disposed substantially around the bent pipe part, characterised in that: the bent pipe part includes: a first bent portion at which an upstream portion of the EGR internal passage is bent away from a gas inflow port of the EGR cooler; a second bent portion located downstream of the first bent portion and configured to bend the EGR internal passage substantially toward the gas inflow port; and an intermediate portion connecting the first bent portion to the second bent portion by being disposed therebetween, the water-cooling passage further comprising a water outlet attached to an end surface of the cylinder head and including therein a plurality of outflow passages configured to distribute cooling water to a plurality of water outflow ports, respectively, the outflow passages and the water outflow ports constituting a portion of the water-cooling passage, wherein a downstream portion of the bent pipe part including the second bent portion is located inside the water outlet and is configured to partially project into a first outflow passage having a largest flow channel cross section among the plurality of outflow passages, and wherein a downstream portion of the bent pipe part other than the portion projecting into the first outflow passage is configured to be in contact with a second outflow passage that is different from the first outflow passage. an engine body including: a combustion chamber in which combustion is performed; and a cylinder head provided in an upper part of the engine body and having a water-cooling passage through which cooling water can flow; a combustion chamber in which combustion is performed; and a cylinder head provided in an upper part of the engine body and having a water-cooling passage through which cooling water can flow; an intake passage connected to the cylinder head and through which intake air can be introduced into the combustion chamber; an exhaust passage connected to the cylinder head and through which exhaust gas can be discharged from the combustion chamber; and an EGR passage connecting the exhaust passage to the intake passage and configured to recirculate the exhaust gas as EGR gas, from the exhaust passage to the intake passage, the EGR passage including: an EGR cooler configured to cool the EGR gas; and an EGR internal passage constituting the EGR passage upstream of the EGR cooler, and including a passage passing through the cylinder head, wherein the EGR internal passage has a bent pipe part and an EGR cooler configured to cool the EGR gas; and an EGR internal passage constituting the EGR passage upstream of the EGR cooler, and including a passage passing through the cylinder head, wherein the EGR internal passage has a bent pipe part and the water-cooling passage is disposed substantially around the bent pipe part, characterised in that: the bent pipe part includes: a first bent portion at which an upstream portion of the EGR internal passage is bent away from a gas inflow port of the EGR cooler; a second bent portion located downstream of the first bent portion and configured to bend the EGR internal passage substantially toward the gas inflow port; and an intermediate portion connecting the first bent portion to the second bent portion by being disposed therebetween, the water-cooling passage a first bent portion at which an upstream portion of the EGR internal passage is bent away from a gas inflow port of the EGR cooler; a second bent portion located downstream of the first bent portion and configured to bend the EGR internal passage substantially toward the gas inflow port; and an intermediate portion connecting the first bent portion to the second bent portion by being disposed therebetween, the water-cooling passage further comprising a water outlet attached to an end surface of the cylinder head and including therein a plurality of outflow passages configured to distribute cooling water to a plurality of water outflow ports, respectively, the outflow passages and the water outflow ports constituting a portion of the water-cooling passage, wherein a downstream portion of the bent pipe part including the second bent portion is located inside the water outlet and is configured to partially project into a first outflow passage having a largest flow channel cross section among the plurality of outflow passages, and wherein a downstream portion of the bent pipe part other than the portion projecting into the first outflow passage is configured to be in contact with a second outflow passage that is different from the first outflow passage.