(EN) One aspect of the present invention is a gas treatment method comprising: an absorption step of bringing a gas to be treated, which contains carbon dioxide and a sulfur compound, into contact with an absorption solution that performs phase separation by carbon dioxide absorption, thereby causing the carbon dioxide and the sulfur compound to be absorbed by the absorption solution; and a first release step of heating the absorption solution that was brought into contact with the gas to be treated to at least a temperature at which the carbon dioxide absorbed in the absorption solution is released from the absorption solution, but below the temperature at which the sulfur compound absorbed in the absorption solution is released from the absorption solution, thereby releasing the carbon dioxide from the absorption solution.
