A storage capacity management system for managing a storage capacity of a battery, including: an upper limit terminal voltage inducing part for inducing an upper limit terminal voltage (Vh) which is a terminal voltage when the storage capacity of the battery is an upper limit storage capacity; a lower limit terminal voltage inducing part for inducing a lower limit terminal voltage which is a terminal voltage when the storage capacity of the battery is a lower limit storage capacity; an upper and lower limit voltage width calculating part for calculating an upper and lower limit voltage width by subtracting the lower limit terminal voltage from the upper limit terminal voltage (Vh); an intermediate voltage difference calculating part for calculating an intermediate voltage difference by subtracting the lower limit terminal voltage from a terminal voltage of the battery; an upper and lower limit voltage ratio calculating part for calculating an upper and lower limit voltage ratio which is a ratio (B/A) of the intermediate voltage difference to the upper and lower limit voltage width; an intermediate determination voltage ratio inducing part for inducing an intermediate determination voltage ratio which differs according to the temperature of the battery, a voltage ratio comparing part for comparing the upper and lower limit voltage ratio with the intermediate determination voltage ratio; and an intermediate storage capacity correcting part for inducing an intermediate storage capacity which is set in advance or is based on the upper limit storage capacity, the lower limit storage capacity and the intermediate determination voltage ratio, when the results of the comparison by the voltage ratio comparing part satisfy a predetermined condition. an upper limit terminal voltage inducing part for inducing an upper limit terminal voltage (Vh) which is a terminal voltage when the storage capacity of the battery is an upper limit storage capacity; a lower limit terminal voltage inducing part for inducing a lower limit terminal voltage which is a terminal voltage when the storage capacity of the battery is a lower limit storage capacity; an upper and lower limit voltage width calculating part for calculating an upper and lower limit voltage width by subtracting the lower limit terminal voltage from the upper limit terminal voltage (Vh); an intermediate voltage difference calculating part for calculating an intermediate voltage difference by subtracting the lower limit terminal voltage from a terminal voltage of the battery; an upper and lower limit voltage ratio calculating part for calculating an upper and lower limit voltage ratio which is a ratio (B/A) of the intermediate voltage difference to the upper and lower limit voltage width; an intermediate determination voltage ratio inducing part for inducing an intermediate determination voltage ratio which differs according to the temperature of the battery, a voltage ratio comparing part for comparing the upper and lower limit voltage ratio with the intermediate determination voltage ratio; and an intermediate storage capacity correcting part for inducing an intermediate storage capacity which is set in advance or is based on the upper limit storage capacity, the lower limit storage capacity and the intermediate determination voltage ratio, when the results of the comparison by the voltage ratio comparing part satisfy a predetermined condition.