To minimize a decrease in line efficiency by taking into account a decrease in the processing capability of a device due to trouble when the processing order of a lot is determined.

This is a production control unit which determines the processing order between lots by processes when each product has plural lots. This device has a load rate determining means 32 which determines device load rates R showing the extents of the loads on the devices used to process lots by the devices, a processing order determining means 33 which determines the processing order PO of plural lots by determining load rate priority according to the device load rates R and integrating the load rate priority with the priority of other elements determining the processing order of the lots, and an output means 23 which outputs the processing order PO.