Backup control means controls processing for backing up data in storage means. In a state in which the storage means is not being supplied with power from the main power supply, a backup power supply supplies power to the storage means in order that backup processing by the backup control means will be performed. A timer measures power-supply time, which is the length of time the backup power supply supplies a voltage equal to or greater than a rated voltage to the storage means in order that backup processing will be performed. Determination means determines whether the power-supply time counted by the timer is shorter than length of a reference backup time. Notification of result of backup processing is given by alert means in accordance with the result of the determination made by the determination means.