A carbon dioxide absorbent includes lithium silicate containing lithium orthosilicate and lithium metasilicate, the lithium metasilicate being contained in an amount of 5% by weight or more to 40% by weight or less with respect to the total amount of lithium orthosilicate and lithium metasilicate, where the lithium metasilicate produced by reaction of the lithium orthosilicate and carbon dioxide is excluded.