A carbon dioxide recovery system (10A; 10B; 10C) comprising: a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine; a main boiler configured to generate steam for driving these turbines, to receive condensed water generated via these turbines, and including a resuperheater configured to resuperheat an emission from the high-pressure turbine; a carbon dioxide absorber configured to absorb and reduce carbon dioxide in flue gas emitted from the main boiler by using a carbon dioxide absorbent; a carbon dioxide recovery unit configured to heat a carbon dioxide absorbent having absorbed the carbon dioxide by using a regenerating superheater and to regenerate a carbon dioxide absorbent by using a absorbent regenerator; an independent auxiliary boiler configured to generate saturated water vapor or almost-saturated water vapor to be supplied to the regenerating superheater in the absorbent regenerator via a steam turbine and to receive condensed water generated via the regenerating superheater, the independent auxiliary boiler having an output smaller than that of the main boiler; the steam turbine being configured to be driven by the saturated water vapor or almost-saturated water vapor from the independent auxiliary boiler and to introduce turbine emission into the regenerating superheater, a CO 2 compressor configured to be driven by the steam turbine and to compress CO 2 gas from the absorbent regenerator, or a power generator configured to be driven by the steam turbine to generate power; wherein the carbon dioxide recovery system (10A; 10B; 10C) is configured to supply carbon dioxide in flue gas emitted from the independent auxiliary boiler to the carbon dioxide absorber. a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine; a main boiler configured to generate steam for driving these turbines, to receive condensed water generated via these turbines, and including a resuperheater configured to resuperheat an emission from the high-pressure turbine; a carbon dioxide absorber configured to absorb and reduce carbon dioxide in flue gas emitted from the main boiler by using a carbon dioxide absorbent; a carbon dioxide recovery unit configured to heat a carbon dioxide absorbent having absorbed the carbon dioxide by using a regenerating superheater and to regenerate a carbon dioxide absorbent by using a absorbent regenerator; an independent auxiliary boiler configured to generate saturated water vapor or almost-saturated water vapor to be supplied to the regenerating superheater in the absorbent regenerator via a steam turbine and to receive condensed water generated via the regenerating superheater, the independent auxiliary boiler having an output smaller than that of the main boiler; the steam turbine being configured to be driven by the saturated water vapor or almost-saturated water vapor from the independent auxiliary boiler and to introduce turbine emission into the regenerating superheater, a CO 2 compressor configured to be driven by the steam turbine and to compress CO 2 gas from the absorbent regenerator, or a power generator configured to be driven by the steam turbine to generate power; wherein the carbon dioxide recovery system (10A; 10B; 10C) is configured to supply carbon dioxide in flue gas emitted from the independent auxiliary boiler to the carbon dioxide absorber.