A gelatin stone having a new polishing mechanism that can polish a free-form surface is proposed in this study. The gelatin based stone can easily control the hardness and the melting point by changing the density, the cooling condition and the kinds of additives. The main conclusions obtained in this study are as follows. The proposed gelatin stone can polish the surface of various materials. The high density of gelatin is suited for a gelatin stone. Surface roughness improves as the polishing time gets longer. Polishing by gelatin stone needs a high-speed relative motion.