A battery pack and a residual battery capacity computing method. A correction coefficient associated with a temperature detected by a temperature detection unit is stored in the storage unit, the correction coefficient is read out and the residual battery capacity is computed based on the correction coefficient and the voltage detected by the voltage detection unit. If a correction coefficient associated with the detected temperature is not stored in the storage unit, a correction coefficient associated with a pre-set temperature ahead and at back of the detected temperature is read out from the storage unit to compute a correction coefficient associated with the detected temperature based on each read-out correction coefficient to compute the residual battery capacity based on the computed correction coefficient and the voltage detected by the voltage detection unit. If there is produced a temperature change in the battery cell, a correction coefficient can be acquired correctly in keeping with such change to enable the residual battery capacity to be computed accurately at all times.