Abstract: This invention has improved the automatic programming method which is used for machining the configuration of a curved surface of a die. The values of X and Y coordinates are calculated by a machining path production device through a curved surface configuration storage device. The value of Z coordinate in the third dimension is obtained by a machining point calculation device. If a curved surface in the Z axis is to be machined two or more times, a judgement circuit decides this and a calculation processing device calculates that the first machining is to be conducted in conformity with the curved surface and the second or later machining is to be skipped for rapid feeding, this decision being stored in a tool path data storing device.