Carbon dioxide-absorbing solution and method of recovering carbon dioxide

A method of recovering carbon dioxide, including bringing gas to be processed containing carbon dioxide (CO₂) and oxygen into contact with the CO₂-absorbing solution according to Claim 1 in an absorption column to form a CO₂-rich solution; subsequently circulating the solution in a regeneration column to thermally release and recover CO₂ and recirculating the absorbing solution as a CO₂-poor solution inside the absorption column; and performing heat exchange between the solution being delivered from the absorption column to the regeneration column and the solution recirculated from the regeneration column to the absorption column, wherein an alkanolamine aqueous solution containing a silicone oil and/or an organosulfur compound represented by the Formula (A) or (B) is added to the solution inside the absorption column and/or the solution recirculated from the regeneration column to the absorption column to adjust the composition of the absorbing solution inside the absorption column so as to include the alkanolamine in an amount of 30% by weight or more and 60% by weight or less, the organosulfur compound in an amount of 0.01% by weight or more and 2% by weight or less, and the silicone oil in an amount of 5 ppm by weight or more and 100 ppm by weight or less.