A CO2 recovery system includes an absorber 2 and a regenerator 3. The absorber 2 includes a CO2 absorbing section 21 and at least one water-washing section 22. The CO2 absorbing section 21 allows flue gas 101 to come into contact with a basic amine compound absorbent 103 so that the basic amine compound absorbent 103 absorbs CO2 in the flue gas 101. The at least one water-washing section 22 allows the decarbonated flue gas 101A in which the amount of CO2 has been reduced in the CO2 absorbing section 21 to come into contact with wash water 104A and 104B to reduce the amounts of the basic amine compounds entrained in the decarbonated flue gas 101A. The regenerator 3 releases the CO2 from the basic amine compound absorbent 103 containing CO2 absorbed therein.