to provide a material monitoring system for biomass plastic from its source , information , such as weight , mass , or volume , in each nth node is transmitted at prescribed in and out timings to a central management server . based on the information , the management server carries out monitoring of the original material &# 39 ; s mass or volume which is presently onsite at the nth node . while material distribution elements will in reality branch off and become complex , the total quantity of the original material which the management server manages does not change . should an error arise in a change in the total quantity of the original material which the management server manages , it will be possible to suspect an illicit event and to investigate the cause thereof based on the management information .