A method of producing a thickened carbonated beverage packed in a container, comprising: mixing an aqueous solution containing a first thickening agent and having a temperature of 0 to 35° C. with a second thickening agent insoluble in water in a temperature range of 0 to 35° C. but soluble in water at a temperature of 60° C. or more to obtain a stock liquid with the second thickening agent dispersed in the solution； dissolving carbon dioxide gas in the stock liquid to obtain a carbonated aqueous solution； filling a container with the carbonated aqueous solution and sealing the container to obtain the carbonated aqueous solution packed in the container； and heating the carbonated aqueous solution packed in the container such that the carbonated aqueous solution has a temperature of 60° C. or more to dissolve the second thickening agent in the solution.
