The surface roughness of castings which had been produced with various high fusing alloys was studied. They had been related with roughness of mould cavity walls and pattern surface, and affected by heating the mould and casting. The results are as follows; 1. Surface roughness of mould cavity walls was reproduced with the surface of pattern, but that was influenced by particle size of refractory in the investment products. 2. Wall surface of mould cavity was the less smoothed, by heating the mould lower. 3. Surface roughness of castings was so reduced, as lowering the mould temperature. 4. Castings surface was roughened partially, which were effected with situations and directions of sprue. 5. Surface roughness of castings produced with the alloy had reacted to investment, was increased.