Current CAM systems are difficult for unskilled engineers to use and are still labor-intensive tasks because of too many conditions to select. In this research, the automatic machining process deciding system was developed. The system analyzes the shape of a 3D-model and extracts manufacturing features considering combinations of feature regions. Each manufacturing feature has the corresponding machining method, so the system decides machining method following them. The system also selects cutting tool considering the shape of manufacturing features and decides machining sequence considering combinations of machining tool. This system enables unskilled user to achieve more efficient machining process.