To provide a method and a device for producing a small size carbonate spring which are developed for widely spreading curing effect of a carbonate spring that belong to a technical field to produce foot bath tub water with effect for both beauty and cure by developing blood capillary special to a high concentration carbonate hot spring as a home use 24-hr bath.

Bath tub water is jetted into a carbon dioxide gas storing space 112 above a device body and then made into fine water particles. After absorbing carbon dioxide gas, the fine water particles pass through a liquid storing part 109 located in the lower portion and the return the bath tub through a drain port 101. A water level of the liquid storing part 109 is controlled by ON/OFF of carbon dioxide gas supply to secure a carbon dioxide gas storing space volume and to prevent the carbon dioxide gas from being discharged to the bath tub. Because the tub water is circulated efficiently absorbing carbon dioxide gas in the carbon dioxide gas storing space, high concentration carbon dioxide spring can be easily produced. On the other hand, a carbon oxide producing bath agent may be used together and, for a low concentration carbon dioxide spring, a carbon dioxide spring can be produced by throwing-in only a bath agent into the liquid storing part. By this invention a carbon dioxide spring may be easily produced. High concentration carbon dioxide water of about 1000 ppm and 40°C may be continuously produced and the concentration can be maintained. That is extremely effective as a foot bath curing device for diabetes.