A carbon dioxide separation and recovery apparatus comprising: an absorber making absorbing liquid absorb carbon dioxide contained in exhaust combustion gas, and discharging the absorbing liquid containing the carbon dioxide; a regenerator supplied with the absorbing liquid discharged from the absorber, eliminating carbon dioxide gas containing steam from the absorbing liquid, and regenerating and discharging the absorbing liquid; a regenerated heat exchanger placed between the absorber and the regenerator and using the absorbing liquid discharged from the regenerator and supplied to the absorber as a heat source to heat the absorbing liquid discharged from the absorber and supplied to the regenerator; and an oxygen eliminating unit eliminating oxygen from the absorbing liquid supplied from the absorber to the regenerator characterized by a first collecting unit and a second collecting unit collecting the oxygen contained in the absorbing liquid, a first flow passage switching unit supplying the absorbing liquid discharged from the absorber to the first collecting unit or the second collecting unit, a second flow passage switching unit supplying the absorbing liquid discharged from the first collecting unit or the second collecting unit to the regenerated heat exchanger, and a regenerating unit recovering the oxygen collected in the second collecting unit in the case where the first flow passage switching unit supplies the first collecting unit with the absorbing liquid, and recovering the oxygen collected in the first collecting unit in the case where the first flow passage switching unit supplies the second collecting unit with the absorbing liquid. an absorber making absorbing liquid absorb carbon dioxide contained in exhaust combustion gas, and discharging the absorbing liquid containing the carbon dioxide; a regenerator supplied with the absorbing liquid discharged from the absorber, eliminating carbon dioxide gas containing steam from the absorbing liquid, and regenerating and discharging the absorbing liquid; a regenerated heat exchanger placed between the absorber and the regenerator and using the absorbing liquid discharged from the regenerator and supplied to the absorber as a heat source to heat the absorbing liquid discharged from the absorber and supplied to the regenerator; and an oxygen eliminating unit eliminating oxygen from the absorbing liquid supplied from the absorber to the regenerator characterized by a first collecting unit and a second collecting unit collecting the oxygen contained in the absorbing liquid, a first flow passage switching unit supplying the absorbing liquid discharged from the absorber to the first collecting unit or the second collecting unit, a second flow passage switching unit supplying the absorbing liquid discharged from the first collecting unit or the second collecting unit to the regenerated heat exchanger, and a regenerating unit recovering the oxygen collected in the second collecting unit in the case where the first flow passage switching unit supplies the first collecting unit with the absorbing liquid, and recovering the oxygen collected in the first collecting unit in the case where the first flow passage switching unit supplies the second collecting unit with the absorbing liquid. a first collecting unit and a second collecting unit collecting the oxygen contained in the absorbing liquid, a first flow passage switching unit supplying the absorbing liquid discharged from the absorber to the first collecting unit or the second collecting unit, a second flow passage switching unit supplying the absorbing liquid discharged from the first collecting unit or the second collecting unit to the regenerated heat exchanger, and a regenerating unit recovering the oxygen collected in the second collecting unit in the case where the first flow passage switching unit supplies the first collecting unit with the absorbing liquid, and recovering the oxygen collected in the first collecting unit in the case where the first flow passage switching unit supplies the second collecting unit with the absorbing liquid.