Processing apparatuses A, B, C, and D are included in a job-shop production line, and process 1 to process 6 are performed by the processing apparatuses A, B, C, B, D, and B, respectively. The processing apparatus B is repeatedly used in process 2, process 4, and process 6; therefore, these processes are key processes. Based on the key processes, process 1 to process 6 are classified into a plurality of groups, and the number of in-process products of each of the groups is counted by a counting unit. According to this, a determining unit determines priority orders of the key processes such that a higher priority is given to a key process in a group having a large number of the in-process products. Thus, it becomes possible to perform determination of the priority orders further according to an actual situation, and to improve production efficiency.