A battery capacity display method to display a full charge capacity of a battery and a residual capacity of the battery, respectively, as a full charge capacity display value and a residual capacity display value, the battery capacity display method includes: correcting the full charge capacity display value and/or the residual capacity display value so as to decrease a difference between the full charge capacity display value and the residual capacity display value when the battery is in the full charge state and the full charge capacity and the residual capacity in the full charge state are different from each other, and displaying a corrected full charge capacity display value and/or a corrected residual capacity display value.