A battery controlling device includes: a voltage detecting unit configured to detect a closed-circuit voltage of a secondary battery; an open-circuit-voltage computing unit configured to compute an open-circuit voltage of the secondary battery; and an assembled-battery controlling unit configured to discriminate whether a computed value computed based on a voltage difference between the closed-circuit voltage and the open-circuit voltage of the secondary battery in a continuous predetermined period is exceeding a permissible value determined in advance or not. If the computed value is exceeding the permissible value determined in advance, the assembled-battery controlling unit outputs a signal that carries out charge/discharge restriction of the secondary battery.