Properties of dry films composed of gelatin and κ-carrageenan were examined. Optical rotation of the blend film changed approximately linearly with the blend composition, suggesting that both polymers form independently their characteristic high-order structures (helices) in the film without strong interaction between them. This is consistent with our microphase separation model to the blend gel. Swelling behavior of the blend films varied with the film composition and the pH of the swelling solution. We discuss the pH dependence of the swelling ratio from the electric charges of the polymers and found that the electrostatic interaction between the gelatin domain and the carrageenan domain is of importance to the deformation by the swelling.