To include an absorber (1006) that brings CO2 absorbent that absorbs CO2 contained in flue gas (1002) into contact with the flue gas to remove CO2 from the flue gas, a regenerator (1008) that strips CO2 from CO2 absorbent (rich solution), which is fed from the absorber through a first feed line L1 and has absorbed CO2, to regenerate CO2 absorbent, thereby acquiring regenerated CO2 absorbent (lean solution) (1009), falling film reboilers (1101-1 and 1101-2) that draw off CO2 absorbent (amine solution) (1033) from near the bottom of the regenerator and reheats regenerated CO2 absorbent via steam (1031), a first liquid-vapor separator (1103) that separates the CO2 absorbent reheated by the falling film reboilers into regenerated CO2 absorbent in which CO2 has been removed and vapor containing CO2, and a second feed line L2 for supplying the separated regenerated CO2 absorbent to the absorber.