An apparatus for estimating a degradation degree of a secondary battery includes a pulse current applying unit that applies a pulse current; a voltage acquiring unit that acquires a charge voltage and a discharge voltage which are produced at the secondary battery by applying the pulse current; a relative value calculation unit that calculates a relative value between the charge voltage and the discharge voltage; a correlation storage unit that stores a correlation between a relative value between the charge voltage and the discharge voltage, and a degradation degree of the secondary battery; and a degradation degree estimation unit that obtains a degradation degree of the secondary battery from the correlation storage unit, based on the relative value calculated by the relative value calculation unit.