A system includes a storage in which information indicative of a degree of degradation, which is a degree of degradation of each of a plurality of battery packs for rent, is stored. The system also includes an electric reader that acquires information indicative of a first degree of degradation, which is a degree of degradation of a first battery pack, which is a battery pack brought by the user. The system further includes a processor that selects, as a second battery pack rented to the user, a battery pack whose degree of degradation is equal to or lower than the first degree of degradation from among the plurality of battery packs for rent when the second battery pack is rented to the user by exchange between the first battery pack and the second battery pack.