STORAGE BATTERY CAPACITY MEASUREMENT DEVICE

A storage battery capacity measurement device is provided in in-plant equipment including a storage battery system connected to an intra-equipment electric wire. The storage battery system includes plural storage batteries connected in parallel to the intra-equipment electric wire. The storage battery capacity measurement device is configured to execute a determining one storage battery among the plural storage batteries as a measurement target storage battery, and at least one storage battery other than the measurement target storage battery as a measurement support storage battery, discharging an electricity amount of the measurement target storage battery from an upper limit to a lower limit, and charging the discharged electricity amount to the measurement support storage battery, and calculating a discharge capacity of the measurement target storage battery, based on an integrated value of a current flowing through the measurement target storage battery during discharge.