To create NC working data capable of individually specifying a NC code for the optimum piercing according to the cut shape and dimension at the time of cutting by NC laser beam machine or the like, capable of specifying a NC code for the optimum beam OFF according to the cut shape and dimension, and further capable of executing high efficiency and high quality cutting.

The automatic programming system is provided with a start/end code registration part 17 capable of registering a plural kinds of NC code for cut-start beam ON and a beam ON/OFF attribute change part 15 changing individually each kind of beam ON attribute added to the required part of cut shape plotted on a screen by the input from a man-machined interface part 21 in the range of the registrable kind of the NC code for cut-start beam ON.