An absorption solvent regeneration device includes: a regenerator for regenerating an absorption solvent by separating CO2 from the absorption solvent which has absorbed CO2; a main rich solvent line for supplying the absorption solvent which has absorbed CO2 to the regenerator; a first heating part for heating the absorption solvent flowing through the main rich solvent line, the first heating part being disposed on the main rich solvent line; and a branch rich solvent line for supplying a part of the absorption solvent flowing through the main rich solvent line to the regenerator, the branch rich solvent line branching from the main rich solvent line. The absorption solvent regeneration device further includes a regulating part for regulating a ratio between a first flow rate of the absorption solvent flowing through the first branch portion and a second flow rate of the absorption solvent flowing through the second branch portion.