To relate unambiguously the execution time in each functional processing formed by dividing the production instruction processing and the product which required the execution time.

A production instructing system includes an input/output control processing part 16 having processing parts 11-14 to perform in lump the input and output processing of messages to be exchanged with the outside or other processing parts 11-14 and acquiring the monitoring information containing the signal designation for transmitting and receiving any message, transmitting/receiving time, and product distinguishing information on the basis of the message associated with the processing parts 11-14 as object to be processed according to the definition contents of a definition file 22 and a monitoring processing part 18 to record the monitoring log information prepared on the basis of the monitoring information in a monitoring log file 24. The monitoring processing part 18 calculates the processing execution time which has been required not only for individual processes but also a series of processes according to the specified combination of processes of the definition file 22 and judges if the obtained processing execution time is due on the basis of the reference total time set in the definition file 22.