The study deals with the tool path generation method for 5-axis control machining in consideration of tool interference with a workpiece. Since 5-axis control cutting tool can take an arbitrary attitude against the workpiece surfaces, it allows us to produce workpieces with a variety of complicated shape. However, a serious problem such as the interference between the cutting tool and the workpiece takes place. Thus, it is strongly required to develop a CAM system to generate the interference-free tool path. A sophisticated interference-free tool path generation method have been already developed by making the most of the concept of configuration space, which expresses the relationship between the tool attitudes and the tool interference. However, since the boundary of the configuration space was formed by a curve interpolation, the operation required much calculation time, and often led to the instability of calculation. In order to solve the above problems, a linear interpolation was employed, instead of the curved one. This results in shortening the formation time of the configuration space and in increasing the robustness in the calculation stability. As a result, it is experimentally found that the CAM system for 5-axis control employing the improved configuration space is capable of producing a closed impeller, which is a typical example of workpieces with complicated overhanging shape.