To provide a production method of carbon dioxide gas-containing hot water significantly improving carbonate spring bathing effects such as blood circulation promotion, a production apparatus for easily producing the carbon dioxide gas-containing hot water, and a tablet for a carbon dioxide gas dissolver.

A carbon dioxide gas dissolver provides carbon dioxide gas-containing hot water by dissolving the carbon dioxide gas in a gas phase in hot water. The production apparatus of carbon dioxide gas-containing hot water combines (1) bicarbonate or (2) bicarbonate and organic acid to be dissolved in the hot water for acquiring the carbon dioxide gas-containing hot water. The carbon dioxide gas is dissolved in hot water with PH of not less than 6.0 and not more than 9.5 under the presence of (1) bicarbonate or (2) bicarbonate and organic acid.