To provide a carbonic acid bath apparatus capable of creating a carbonate spring with a large free carbon dioxide concentration in a simple constitution at low cost by efficiently dissolving carbon dioxide in bathtub water.
A vessel body 30 having a hollow part 29 is provided at the end of a circulating track 14 of a bathtub hot water circulating device 10 circulating the hot water in the bathtub 12 by a pump 15, and the bathtub hot water and the carbon dioxide are circulated in the hollow part 29 and jetted out inside the bathtub 12 as fine air bubbles. This constitution can efficiently dissolve the carbon dioxide in the bathtub hot water to create the carbonate spring with the large free carbon dioxide concentration in the simple constitution at the low cost.
ONO HIDEKI
KONDO MASAMITSU
Tomoyasu Sakaguchi
Hiroki Naito