A carbon dioxide separation and capture apparatus comprising: an absorption tower configured to cause an absorbing liquid to absorb a carbon dioxide gas contained in an exhaust gas; a blower configured to supply the carbon dioxide gas to the absorption tower with a blower output that is within a predetermined output range; a regeneration tower configured to cause the absorbing liquid supplied by a pump from the absorption tower to release the carbon dioxide gas; a reboiler configured to heat the absorbing liquid discharged from the regeneration tower and to supply a steam generated therefrom to the regeneration tower, wherein the absorbing liquid is heated with a heating medium; a concentration meter configured to measure concentration of the carbon dioxide gas in the exhaust gas; a first flow rate control valve configured to adjust a circulation flow rate of the absorbing liquid circulating between the absorption tower and the regeneration tower with a first opening degree; a second flow rate control valve configured to adjust a flow rate of the heating medium with a second opening degree; and a control device configured to control the blower, the first flow rate control valve, and the second flow rate control valve, wherein the control device includes a storage unit storing a plurality of relationships between a flow rate of the carbon dioxide gas in the exhaust gas, and a sum of energy of a heat to be supplied with the heating medium, the power of the blower and the power of the pump, each of the plurality of relationships corresponding to each of a plurality of predetermined target amounts of captured carbon dioxide gas, a flow rate determining unit configured to calculate a flow rate range of the carbon dioxide gas based on the concentration measured by the concentration meter and the predetermined output range of the blower, and determine the flow rate based on at least one of the plurality of relationships stored in the storage unit so that the sum of energy is to be the least within the calculated flow range, and a control unit configured to control the blower output, the first opening degree and the second opening degree based on the flow rate determined with the flow rate determining unit. an absorption tower configured to cause an absorbing liquid to absorb a carbon dioxide gas contained in an exhaust gas; a blower configured to supply the carbon dioxide gas to the absorption tower with a blower output that is within a predetermined output range; a regeneration tower configured to cause the absorbing liquid supplied by a pump from the absorption tower to release the carbon dioxide gas; a reboiler configured to heat the absorbing liquid discharged from the regeneration tower and to supply a steam generated therefrom to the regeneration tower, wherein the absorbing liquid is heated with a heating medium; a concentration meter configured to measure concentration of the carbon dioxide gas in the exhaust gas; a first flow rate control valve configured to adjust a circulation flow rate of the absorbing liquid circulating between the absorption tower and the regeneration tower with a first opening degree; a second flow rate control valve configured to adjust a flow rate of the heating medium with a second opening degree; and a control device configured to control the blower, the first flow rate control valve, and the second flow rate control valve, wherein the control device includes a storage unit storing a plurality of relationships between a flow rate of the carbon dioxide gas in the exhaust gas, and a sum of energy of a heat to be supplied with the heating medium, the power of the blower and the power of the pump, each of the plurality of relationships corresponding to each of a plurality of predetermined target amounts of captured carbon dioxide gas, a flow rate determining unit configured to calculate a flow rate range of the carbon dioxide gas based on the concentration measured by the concentration meter and the predetermined output range of the blower, and determine the flow rate based on at least one of the plurality of relationships stored in the storage unit so that the sum of energy is to be the least within the calculated flow range, and a control unit configured to control the blower output, the first opening degree and the second opening degree based on the flow rate determined with the flow rate determining unit. calculate a flow rate range of the carbon dioxide gas based on the concentration measured by the concentration meter and the predetermined output range of the blower, and determine the flow rate based on at least one of the plurality of relationships stored in the storage unit so that the sum of energy is to be the least within the calculated flow range, and a control unit configured to control the blower output, the first opening degree and the second opening degree based on the flow rate determined with the flow rate determining unit.