For the effective re-use of parts, each re-usable part is required to be under appropriate management throughout their life cycle. A hindrance to the circulation of re-used parts is behavior of users. The flow of re-used parts around the user is uncontrollable and unpredictable. Authors are proposing "Part agent system" that is the combination of network agent called "Part agent" and radio frequency identification chip RFID. This paper discusses the mechanisms how Part agents use the operation history of the parts and the user's preference on maintenance of the parts to support their effective reuse.