A CO2 recovery unit includes an absorber that reduces CO2 in flue gas (101) discharged from a combustion facility (50) by absorbing CO2 by an absorbent, a regenerator that heats the absorbent having absorbed CO2 to emit CO2, and regenerates and supplies the absorbent to the absorber, and a regenerating heater that uses steam (106) supplied from the combustion facility (50) for heating the absorbent in the regenerator and returns heated condensed water (106a) to the combustion facility (50). The CO2 recovery unit further includes a condensed water/flue gas heat exchanger (57) that heats the condensed water (106a) to be returned from the regenerating heater to the combustion facility (50) by heat-exchanging the condensed water (106a) with the flue gas (101) in a flue gas duct (51) in the combustion facility (50).