Provided herein is a film-forming composition for use in the preparation of a soft capsule, which comprises (a) acid-decomposed waxy corn starch (b) a gelling agent and (c) a plasticizer. A soft capsule comprising a shell produced using the film-forming composition disclosed herein has excellent characteristic properties with respect to physical strength, disintegration ability, odor, taste, color and lack of adhesion and also exhibits excellent stability with time.