1. A display method of a synchronous control program for controlling driving of a multi-axis synchronous control device which executes positioning control while synchronizing axes with each other the method comprises: displaying on one screen of a display device a synchronous control program of a multi-axis configuration, in which driving software modules are coupled together into the same axis, among synchronous control programs generated by a control device and respectively corresponding to axes on which a multi-axis synchronous control device executes positioning control and outputs, by the control device, the generated synchronous control programs, and selecting either execution or non-execution of a module operation of each of a plurality of software modules that constitute the synchronous control program of a multi-axis configuration after displaying the software modules on the display screen of the display device in a state where the software modules respectively correspond to a plurality of cells arranged in a matrix, and displaying the synchronous control program of a multi-axis configuration in such a manner that software modules having been selected as execution at the selecting step are directly connected to each other by removing cells that correspond to software modules having been selected as non-execution at said selecting, while storing a coupling relationship between the software modules having been selected as execution at the selecting.