Battery pack, charging control method, and application device

A battery pack having a secondary battery (1) and a circuit that controls charging and discharging of the secondary battery is disclosed. The battery pack has a computer (10) and a charging control section. The computer communicates with another computer (31) disposed in a charging device (30) and authenticates the charging device. The charging control section, controlled by the computer, supplies a charging current to the secondary battery when the charging device has been successfully authenticated and shuts off the charging current when the charging device has not been successfully authenticated.