A CO2 recovery device includes a cooling tower including a cooling unit for bringing the flue gas, which contains CO2, into contact with water so as to cool flue gas; a CO2-absorbing unit for bringing the flue gas into contact with a CO2 absorbent (lean solution) so as to remove CO2 from flue gas; and a regenerator including an absorbent regenerating unit for releasing CO2 from a rich solution so as to regenerate the CO2 absorbent. The CO2-absorbing unit includes: a cocurrent flow CO2-absorbing unit provided in a cocurrent flow CO2 absorber, for bringing the flue gas into contact with the CO2 absorbent in a cocurrent flow so as to remove CO2 from flue gas and a countercurrent CO2-absorbing unit provided in a CO2 absorber, for bringing the flue gas into contact with the CO2 absorbent in a countercurrent flow so as to remove CO2 from flue gas.