In an automatic programming system for a two-saddle NC turret lathe, shape definition and machining data for defining a machining condition for each machining step are input at each machining step together with a machining code indicating the machining from machining step input apparatus, and stored in a memory. A series of machining steps to be performed by each saddle is set in steps S1 to S9 by assigning, with a machining assigning/setting apparatus, either a machining code indicating the machining condition at each of the series of the machining steps or a wait command. Then, the machining program for each saddle is automatically created by program creating apparatus in accordance with the set data and stored data.