PURPOSE: To automatically prevent the error of setting concerning control, for which the change of execution order is not permitted, by performing display so as to easily discriminate the execution order of respective processes concerning the order controller for controlling the order according to start time and stop time set for each of plural processes.

CONSTITUTION: A second storage means 121 to be read/written by a control arithmetic means 11 stores a class code K expressing the discrimination of whether the change of execution order is permitted for each process or not and process data PD1, PD2... of respective processes composed of a process number PN, start time PST and end time PET and when the class code K is any code not to permit the change of execution order, concerning the process to which the start time is set, the start time is compared with that of processes before and after that process in the order of start, but when the class code is any value to exchange the order of start with the preceding and following processes, the start time is automatically changed and displayed so as to set it between the already set preceding and following processes. When displaying the process data, on the other hand, they are displayed in the order of processes from the earliest time while referring to the start time PST.