A battery degradation degree estimation device, comprising: a total degradation degree detection unit configured to obtain a total output characteristics integration value from a reference timing up to present, to calculate a present cycle degradation degree on the basis of the obtained total output characteristic integration value and a cycle degradation characteristic stored in advance, to calculate a present storage degradation degree on the basis of the time from the reference timing up to present and a storage degradation characteristic stored in advance and to detect a present total degradation degree of a battery on the basis of the present cycle degradation degree and the present storage degradation degree; a cycle degradation estimation unit configured to estimate a future cycle degradation degree due to charge/discharge of the battery; a storage degradation estimation unit configured to estimate a future storage degradation degree over time inside the battery on the basis of the present storage degradation degree and the storage degradation characteristics; a battery degradation estimation unit configured to estimate a future battery degradation degree; characterized by the cycle degradation estimation unit being configured to estimate the future cycle degradation degree by obtaining an integration value during a unit period of an output characteristic, predicting a future integration value on the basis of the obtained integration value and estimating the future cycle degradation degree on the basis of the predicted integration value and a cycle degradation characteristic stored in advance; and the battery degradation estimation unit being configured to estimate the future battery degradation degree on the basis of the present total degradation degree, the future cycle degradation degree and the future storage degradation degree. a total degradation degree detection unit configured to obtain a total output characteristics integration value from a reference timing up to present, to calculate a present cycle degradation degree on the basis of the obtained total output characteristic integration value and a cycle degradation characteristic stored in advance, to calculate a present storage degradation degree on the basis of the time from the reference timing up to present and a storage degradation characteristic stored in advance and to detect a present total degradation degree of a battery on the basis of the present cycle degradation degree and the present storage degradation degree; a cycle degradation estimation unit configured to estimate a future cycle degradation degree due to charge/discharge of the battery; a storage degradation estimation unit configured to estimate a future storage degradation degree over time inside the battery on the basis of the present storage degradation degree and the storage degradation characteristics; a battery degradation estimation unit configured to estimate a future battery degradation degree; characterized by the cycle degradation estimation unit being configured to estimate the future cycle degradation degree by obtaining an integration value during a unit period of an output characteristic, predicting a future integration value on the basis of the obtained integration value and estimating the future cycle degradation degree on the basis of the predicted integration value and a cycle degradation characteristic stored in advance; and the battery degradation estimation unit being configured to estimate the future battery degradation degree on the basis of the present total degradation degree, the future cycle degradation degree and the future storage degradation degree.