To accurately indicate the residual capacity of a battery which has become inactive.

In the method for indicating residual capacity, calculating the residual capacity is calculated from a charge capacity of a secondary battery and indicated. In the method for indicating a residual capacity, whether the battery is an inactive battery or not is judged when starting charge. For the battery judged as an inactive battery, the charge efficiency is corrected to a corrected charge efficiency lower than that in a charge state where the inactiveness is eliminated in an activation charge process for charging the inactive battery, and the residual capacity is calculated from the corrected charge efficiency and the charge capacity for indication.