With a progress of CAD/CAM system and CG software, design and processing of more complicated shape is enabled. Machine tools having more than five axes are used for processing of this complicated shape, and processing of high-flexibility shape it is impossible for three-axis machine tool is enabled. In this research, turning center is used for an example of multi-axis machine tool. For a way of high-efficiency processing, a new rough cutting process by using simplified polygon model is suggested, tool path calculation method of that new processing is developed, and result of efficiency improvement by this developed process is considered and rough machining with the tool path.