A storage battery (1) including an electric storage unit (10), an auxiliary electric storage unit (11) connected to the electric storage unit (10) in parallel, a temperature measurement unit (13) measuring a temperature, and a charge and discharge control unit (14) controlling charge and discharge of the electric storage unit (10) and the auxiliary electric storage unit (11), in which the charge and discharge control unit (14) changes an SOC (a charge completion SOC) of the electric storage unit (10) and the auxiliary electric storage unit (11) in a charge completion state of not allowing any more charge according to a measurement result of the temperature measurement unit (13), increases the charge completion SOC of the auxiliary electric storage unit (11) when the charge completion SOC of the electric storage unit (10) decreases, and decreases the charge completion SOC of the auxiliary electric storage unit (11) when the charge completion SOC of the electric storage unit (10) increases.