To provide a composition and a method for producing a carbonic acid gas-containing soft jelly beverage in an airtight container suitable for drinking by pouring the beverage from the container after gently shaking the container several times to break the jelly product or for sucking through a drinking straw inserted in the container. Mixing 0.3% (w/v) or less (total amount) of a gelatinizer containing kappa carrageenan in an amount of 0.001 % (w/v) or more to less than 0.035% (w/v) to a beverage stock, adding a carbonate to the resultant mixture, charging a container with the carbonic acid gas-containing liquid mixture, subjecting the container to a heat treatment of 700C to 800C for 10 to 20 minutes to melt and dissolve the gelatinizer, stirring the liquid mixture having the gelatinizer melted and dissolved therein to a homogeneous state, and cooling the mixture.