To provide a carbonated hot water preparation device which is made lightweight and sanitary.

The carbonated hot water preparation device is a device for preparing carbonated hot water by passing hot water in a membrane type gaseous carbon dioxide dissolving vessel and simultaneously supplying gaseous carbon dioxide from a membrane type gaseous carbon dioxide supply device to the gaseous carbon dioxide dissolving vessel to dissolve the gaseous carbon dioxide in the hot water and the gaseous carbon dioxide supply device is a device for supplying gaseous carbon dioxide to the gaseous carbon dioxide dissolving vessel from a gaseous carbon dioxide introducing pipe 4 by charging a tablet containing a carbonate (or an acid) into an aqueous solution of an acid (or a carbonate) in a reaction vessel B to cause the chemical reaction to generate gaseous carbon dioxide. Zeolite or dry ice can be charged into the reaction vessel B in place of the carbonate or the acid.