To provide a system to easily secure the discharging performance of condensed water generated by cooling exhaust gas which is refluxed.

The system comprises an exhaust passage R for making exhaust gas flow, reflux flow passages 14, 16 for connecting the exhaust passage R and an intake gas side, an in-head passage (pool) 15 for collecting the condensed water generated by cooling the exhaust gas, and a drainage passage 20 capable of sucking the condensed water collected in the in-head passage (pool) 15 by using the flow of the exhaust gas flowing the exhaust passage R, and can discharge the condensed water to the exhaust passage R. The drainage passage 20 is formed with gaskets 18, 19.