In a conventional automatic programming system developed for turning with a CNC lathe, NC data such as tool path, feed and rotational speed of spindle are automatically generated, when the desired shape of products, and tool and workpiece materials are specified. However, for turning of a workpiece having large length and small diameter, variation in the finished diameter along the rotational axis yields due to workpiece deflection caused by the cutting force. In the case of a shaft that requires machining using multiple tool paths, the magnitude of machining error also varies in accordance with the sequence of the turning process. To reduce the machining error in the diameter, elastic deformation of the workpiece due to cutting force, whose components are obtained through a cutting model and energy method proposed by Usui et al., is considered in the generating process of the tool path. In the analysis for chuck-center work, a finite element model of a rolling center, in which experimental results of bending test are applied, is used. From the comparison of the machining error obtained with turning test for compensated and uncompensated tool paths, it is confirmed that the proposed method is effective in reduction of machining error.