To evaluate the degradation of a power storage system without stopping the functions of the power storage system. [Solution] A storage battery evaluating device according to an embodiment of the present invention is provided with a data generating unit and a degradation evaluating unit. On the basis of a current value and a voltage value which are measured from a power storage device in which charging and discharging are controlled according to charging and discharging command values, the data generating unit generates a plurality of pieces of correspondence data between the charge amount and the voltage value of the power storage device. The degradation evaluating unit evaluates the degradation state of the power storage device on the basis of the distribution of the voltage value of the correspondence data belonging to a first charge amount range, when the distribution of first charging and discharging command values, which are the charging and discharging command values by which the correspondence data belonging to the first charge amount range are obtained by means of the charging and discharging control, satisfies a predetermined condition.