Problem: Since the production processing and assembly time, as well as the holding time, for each process in the production line cannot be accurately obtained, it is impossible to determine where to start in making process improvements aimed at raising productivity. Obtaining the progress status for each process in the production line is an important factor in achieving supply chain management (SCM), but it is extremely difficult to control this on a host computer because the processes are split into several branches and then merged. Mount a Data Carrier (ID Tag) onto the pallet carrying the product, or onto a workpiece. In addition to product information, write the work start and end times as they occur for each process onto the Data Carrier. Then, at the final process, read the time data that was written for each process and create a graph containing the process history and corresponding time data to analyze the processes. When the work at each process ends, write the process end flag data and instructions for the next process onto the Data Carrier.