A device for assessing an extent of degradation of a secondary battery, includes: a determination unit that determines whether or not a value of current flowing in the secondary battery is less than a predetermined value; a first
voltage measurement unit that takes a time point at which it is determined by the determination unit that the value of the current is less than the predetermined value as being a
start time point of a specific interval, and that measures a first
battery voltage of the secondary battery at the
start time point; a first charge amount calculation unit that obtains a first charge amount corresponding to the secondary battery based upon the measured first
battery voltage; a second
voltage measurement unit that, after the first
battery voltage has been measured by the first
voltage measurement unit, takes a time point at which it is determined by the determination unit that the value of the current is less than the predetermined value as being an end time point of the specific interval, and that measures a second battery voltage of the secondary battery at the end time point; a second charge amount calculation unit that obtains a second charge amount corresponding to the secondary battery based upon the measured second battery voltage; an integrated current amount calculation unit that obtains an integrated amount of the current flowing in the secondary battery during the specific interval; and a charge capacity calculation unit that obtains a difference between the first charge amount and the second charge amount, and that calculates a charge capacity by dividing the integrated amount of the current by the difference.