A system for managing a transaction of an item between first and second users includes a first lock attached to the item, a storage unit having a second lock attached thereto and physically storing the item, and a processor that manages a first privilege to open the first lock and a second privilege to open the second lock. The processor performs management so that a holder of the first and second privileges is the first user. Upon receiving, from the storage unit, information indicating the second lock being opened, the processor performs management so that a first transaction is concluded in which the first user tentatively receives the item from the second user. Upon receiving, from the first lock, information indicating the first lock being opened, the processor performs management so that a second transaction is concluded in which the first user inspects the item and finally receives the item.