To perform charge/discharge control of a storage battery at an appropriate timing. In a battery controller 107, a battery information acquisition unit 201 acquires information on the storage battery. A degradation progression rate calculation unit 202 calculates a degradation progression rate of the storage battery based on the information acquired by the battery information acquisition unit 201. A limit value setting unit 203 sets a limit value for controlling charge/discharge of the storage battery based on the degradation progression rate calculated by the degradation progression rate calculation unit 202. A timing determination unit 204 determines a timing at which the limit value needs to be output based on the information acquired by the battery information acquisition unit 201. A limit value output unit 205 outputs the limit value to a host controller 112 based on the timing determined by the timing determination unit 204.