A cooling system is mounted on an internal combustion engine equipped with an EGR device including an EGR passage. The cooling system includes: an intercooler disposed in the intake passage; an EGR cooler disposed in the EGR passage; a condensed water discharger configured to discharge condensed water generated in the EGR cooler from the EGR passage; a radiator configured to cool a first coolant to or below a dew point of the EGR gas flowing into the EGR cooler; a first circulation flow path configured to circulate the first coolant in the order of the radiator, the EGR cooler, and the intercooler; and a pump disposed in the first circulation flow path and configured to circulate the first coolant such that an outlet gas temperature of the EGR cooler is equal to or lower than the dew point of the EGR gas flowing into the EGR cooler.