Battery charging rate calculation device

Battery charging rate calculating unit (100) is, SOCI calculation outputs SOCV calculating unit that outputs a first charging rate calculated based on the voltage data and (5), the second charging rate calculated based on the current data part (6), the effective charge rate, and the current data, and the estimated impedance voltage calculating unit that calculates an impedance voltage value (12) based on the range in a given that the impedance voltage value is distinguished by a predetermined threshold value determines that it has settled over time, settling judgment unit that outputs the determination result (7), on the basis of the determination result, when the impedance voltage value has settled, the first charging rate It said output as an effective charging rate, otherwise, comprises a SOC determination unit (20) for outputting the second charging rate as the available charge rate.