PURPOSE: To properly display a control purpose by graphically displaying the contents of a function module set file, an operation transition set file, and a program file automatically generated based on a program conversion algorithm.

CONSTITUTION: A CPU 11 performs an operation processing in accordance with a system program stored in a ROM 12. A RAM 13 is connected to the CPU 11. A RAM 14 where function models are stored, a RAM 15 where the function module set file is stored, a RAM 16 where the operation transition set file is stored, and a RAM 17 where the program file is stored are included in the RAM 13. Further, a RAM 18 where a plotting control program to plot various data or the like on a display device is stored is connected to the CPU 11. Various data or the like are displayed on a display device 21, and data or the like for generating a program is inputted from a keyboard 22 by an operator.