A battery control device includes a unit to measure a voltage of a battery, a unit to measure an electric current of the battery, and a control unit to calculate an open-circuit voltage of the battery based on the voltage and the electric current of the battery, and to calculate a battery residual quantity ratio of the battery by use of relative information and the calculated open-circuit voltage, wherein the control unit calculates a charge quantity ratio of the battery by subtracting a battery residual quantity ratio at charge ending time from a battery residual quantity ratio at charge starting time, calculates a value obtained by multiplying the charge quantity ratio by a correction coefficient as a charging-discharging count of the battery, and integrates the charging-discharging count each time the charging-discharging count is calculated.