Abstract: An automatic programming system is incorporated in a numerical controller which controls the operation of a machine tool connected thereto in accordance with a numerical control program. The programming system is designed to automatically program the numerical control program based upon machining information which is manually input by means of a data input device in an interactive mode for defining machinings to be effected on a workpiece. The programming apparatus includes means for automatically determining the machining order of a plurality of machinings on a workpiece in such a manner that any machining needing a higher accuracy is carried out later than any other machining needing a lower accuracy.