An inquiry system is provided in which an inquiry unit of a user of a machine and/or a device makes inquiries related to the machine and/or the device to inquiry a plurality of center systems of suppliers, and includes: a relay device which connects the inquiry unit and the inquiry center systems; and a storage unit which stores first and second identification information related to the machine and/or the device, the inquiry unit includes: an acquisition unit which acquires the first identification information; and a first communication unit which transmits the first identification information acquired to the relay device, the relay device includes: a second communication unit which communicates between the inquiry unit and the inquiry center systems; and a selection unit which selects, based on the first and second identification information, the inquiry center system and the second communication unit connects the inquiry unit and the inquiry center system.