Competitive power is rapidly manufacture product required consumers. Therefore, modern industry have changed from small item many production to many item small production, rapid production is necessary thing at the product development. Thus, rapid prototyping is appeared. If the graphic model was made by CAD, the production can be made in short term. That provide what the part was directly tested by the worker. It provide believable data. This study is Imfluence of Surface roughness on Rapid prototyping by FDM(Fused deposition modeling).