For the restoration of excavated pottery, gypsum has been used exclusively. Recently, however, synthetic resins have come to be partly employed. A mixture of epoxy resin emulsion, baked clay powder and glass microballoon is quite good as a restoration material for imitating the porous texture of excavated pottery. However, the mixture has some disadvantages, including the long curing time and weaker strength. In order to improve the mixture, the authors conducted experiments by adding a silane coupling agent gamma-glycidoxypropyltrimethoxysilane. The agent was added in the range from 0 to 5% of the mixture. The new materials thus obtained have the following characteristics superiorto gypsum. 1) The toughness can be controlled by changing the ratio of the resin and fillers, and the curing time can also be controlled from 0.5 to some ten hours by changing the quantity of the coupling agent and the temperature. 2) The strength is much greater than gypsum. 3) The adhesion to the pottery is better. 4) The texture and hardness of the pottery can be imitated by changing the combination of the components of the material.