A control device for a machine tool to produce a plurality of different-shaped products efficiently and successively is provided. In the control device, each driving shaft of modules M1, M2, M3 is assigned to different control systems. The device includes: a multi-system program storage part (30) for storing a plurality of multi-system programs to machine a workpiece in different shapes, a multi-system program dividing part (31) for dividing the multi-system programs into machining programs, a divided program storage part (32) for storing the divided machining programs individually, a system-based program storage part (34) for storing the machining programs for the respective control systems, and a machining program selection part (33) for selecting the machining program from the divided program storage part (32) in accordance with the machining step to be executed and for storing the selected machining program in the system-based program storage part (34) for the respective control systems.