A carbon dioxide absorbent comprising a chain amine, a cyclic amine, a solvent, and an acid, wherein the chain amine is a compound expressed by Formula, R 1 in Formula is hydrogen or an alkyl chain having at least one hydroxyl group and 1 to 7 carbon atoms, R 2 in Formula is an alkyl chain having at least one hydroxyl group and 1 to 7 carbon atoms, R 3 in Formula is hydrogen, a straight alkyl chain having 1 to 7 carbon atoms, a branched alkyl chain having 1 to 7 carbon atoms, or a cyclic alkyl chain having 5 to 7 carbon atoms, wherein the cyclic amine is at least one compound selected from the group consisting of a compound expressed by Formula, a compound expressed by Formula, and a compound in which structures expressed by Formulas and are linked with each other by a carbon chain, in Formula is an alkyl chain having 1 to 3 carbon atoms, optionally has an organic group including nitrogen as a side chain, and optionally has a hydroxyl group as a side chain, R 5 in Formula is an alkyl chain having 2 to 3 carbon atoms, optionally has an organic group including nitrogen as a side chain, and optionally has a hydroxyl group as a side chain, R 6 in Formula is hydrogen or a straight or branched alkyl chain having 1 to 4 carbon atoms, and optionally has a hydroxyl group, R 7 in Formula is hydrogen or a straight or branched alkyl chain having 1 to 4 carbon atoms, and optionally has a hydroxyl group, R 8 in Formula is a straight alkyl chain having 4 to 7 carbon atoms, optionally has an organic group including nitrogen as a side chain, and optionally has a hydroxyl group, and R 9 in Formula is hydrogen or a straight or branched alkyl chain having 1 to 4 carbon atoms, and optionally has a hydroxyl group, wherein a total amount of the amines in the carbon dioxide absorbent is 20 mass% or more to 80 mass% or less, a molar ratio of the cyclic amine to the acid is 1.0: 0.1 or more to 1.0: 1.9 or less, and the acid is at least one selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, hydroiodic acid, acetic acid, citric acid, formic acid, gluconic acid, lactic acid, oxalic acid, tartaric acid, an organic acid having a sulfo group expressed by Formula, and an organic acid having a sulfo group expressed by Formula, R 10 in Formula is an organic group including an alkyl group, an aryl group, or an alkyl group and an aryl group, optionally including an amino group, a hydroxyl group, or an amino group and a hydroxyl group, and having a straight chain structure with 1 to 5 carbon atoms in the straight chain or a branched structure, and R 11 in Formula is an organic group having an alkyl group, or an amino group and an alkyl group, and having 2 to 5 carbon atoms in a straight chain, the acid is ionized, a pH of the carbon dioxide absorbent is 9.5 or more to 10.8 or less, and the acid has a pKa of 6.0 or less. R 10 -SO 3 H HO 3 S-R 11 -SO 3 H wherein the chain amine is a compound expressed by Formula, R 1 in Formula is hydrogen or an alkyl chain having at least one hydroxyl group and 1 to 7 carbon atoms, R 2 in Formula is an alkyl chain having at least one hydroxyl group and 1 to 7 carbon atoms, R 3 in Formula is hydrogen, a straight alkyl chain having 1 to 7 carbon atoms, a branched alkyl chain having 1 to 7 carbon atoms, or a cyclic alkyl chain having 5 to 7 carbon atoms, wherein the cyclic amine is at least one compound selected from the group consisting of a compound expressed by Formula, a compound expressed by Formula, and a compound in which structures expressed by Formulas and are linked with each other by a carbon chain, in Formula is an alkyl chain having 1 to 3 carbon atoms, optionally has an organic group including nitrogen as a side chain, and optionally has a hydroxyl group as a side chain, R 5 in Formula is an alkyl chain having 2 to 3 carbon atoms, optionally has an organic group including nitrogen as a side chain, and optionally has a hydroxyl group as a side chain, R 6 in Formula is hydrogen or a straight or branched alkyl chain having 1 to 4 carbon atoms, and optionally has a hydroxyl group, R 7 in Formula is hydrogen or a straight or branched alkyl chain having 1 to 4 carbon atoms, and optionally has a hydroxyl group, R 8 in Formula is a straight alkyl chain having 4 to 7 carbon atoms, optionally has an organic group including nitrogen as a side chain, and optionally has a hydroxyl group, and R 9 in Formula is hydrogen or a straight or branched alkyl chain having 1 to 4 carbon atoms, and optionally has a hydroxyl group, wherein a total amount of the amines in the carbon dioxide absorbent is 20 mass% or more to 80 mass% or less, a molar ratio of the cyclic amine to the acid is 1.0: 0.1 or more to 1.0: 1.9 or less, and R 10 in Formula is an organic group including an alkyl group, an aryl group, or an alkyl group and an aryl group, optionally including an amino group, a hydroxyl group, or an amino group and a hydroxyl group, and having a straight chain structure with 1 to 5 carbon atoms in the straight chain or a branched structure, and R 11 in Formula is an organic group having an alkyl group, or an amino group and an alkyl group, and having 2 to 5 carbon atoms in a straight chain, the acid is ionized, a pH of the carbon dioxide absorbent is 9.5 or more to 10.8 or less, and the acid has a pKa of 6.0 or less. R 10 -SO 3 H HO 3 S-R 11 -SO 3 H