A battery pack includes a secondary battery, a circuit having a consumer consuming power of the battery, terminals charging or discharging the pack, a switch that, when the voltage of the battery reaches the discharge cutoff voltage, is opened to stop discharge of the battery through the terminals, and a controller performing a first discharge operation activating the circuit and causing the consumer to consume a remaining power of the battery until a voltage of the battery reaches a first threshold value, higher than the discharge cutoff voltage, and stopping, when the voltage of the battery reaches the first threshold value, the first discharge operation. The controller also performs a second discharge operation activating the circuit and causing the consumer to consume the remaining power of the battery until the voltage of the battery reaches a third threshold value, lower than the discharge cutoff voltage.