In a method, when a first information terminal, which is provided with a wireless communication device capable of communicating with a first wireless communication device provided in a storage battery pack and which retains first identification information indicating a user of the storage battery pack, comes into close proximity with the first wireless communication device (S11), the first information terminal is registered in registration information as a first type of information terminal capable of altering the registration information, the registration information being stored in a storage device provided inside or outside of the storage battery pack, and being of information terminals capable of acquiring information relating to the storage battery pack stored in the storage device (S12).