The molding accuracy of 3 D Printer s by the Stereolithography STL) is said to be superior to that of the Fused Deposition Modeling ( In this work, using 3 D Printer s by STL, the 3D printed objects corresponded tenon and hole were produced, and their sizes were measured. The dimensional differences between the base size and product size were evaluated, and molding accuracy was discussed based on that Also, the molding accuracy between STL and FDM was compared.