A processing instructing device, comprising: a first communication unit configured to communicate information for controlling an operation of a plurality of processing devices with the plurality of processing devices that process a workpiece; a second communication unit configured to communicate information with a conveyance control device that is configured to control an operation of a conveyance device that conveys the workpiece to the plurality of processing devices; a third communication unit configured to communicate information which indicates a processing content for the workpiece in the processing device with a processing execution control device that is configured to control the operations of the processing device and the conveyance device; an arrival time predicting unit configured to predict, based on the information received by the second communication unit, a time when the conveyance device arrives at one of the plurality of processing device; a finish time predicting unit configured to receive information from the first communication unit indicating that a processing on the workpiece in the one processing device has been finished or, based on the information received by the first communication unit, predict a time when the processing on the workpiece in the one processing device is finished; and a processing instructing unit configured such that, when a cumulative value of processings on workpieces according to production in the one processing device, is equal to or larger than a first set cumulative-value and a length of time between the time predicted by the finish time predicting unit and the time predicted by the arrival time predicting unit is equal to or larger than a predetermined length of time, the processing instructing unit is configured to cause processing control information, which instructs the execution of device state improving treatment, to be transmitted to the one processing device by the first communication unit. a first communication unit configured to communicate information for controlling an operation of a plurality of processing devices with the plurality of processing devices that process a workpiece; a second communication unit configured to communicate information with a conveyance control device that is configured to control an operation of a conveyance device that conveys the workpiece to the plurality of processing devices; a third communication unit configured to communicate information which indicates a processing content for the workpiece in the processing device with a processing execution control device that is configured to control the operations of the processing device and the conveyance device; an arrival time predicting unit configured to predict, based on the information received by the second communication unit, a time when the conveyance device arrives at one of the plurality of processing device; a finish time predicting unit configured to receive information from the first communication unit indicating that a processing on the workpiece in the one processing device has been finished or, based on the information received by the first communication unit, predict a time when the processing on the workpiece in the one processing device is finished; and a processing instructing unit configured such that, when a cumulative value of processings on workpieces according to production in the one processing device, is equal to or larger than a first set cumulative-value and a length of time between the time predicted by the finish time predicting unit and the time predicted by the arrival time predicting unit is equal to or larger than a predetermined length of time, the processing instructing unit is configured to cause processing control information, which instructs the execution of device state improving treatment, to be transmitted to the one processing device by the first communication unit.