The present invention provides a control device of a secondary battery. The control device of the secondary battery using, as a positive electrode material, a positive electrode active material that shows a difference of an open circuit voltage curve between during charge and discharge, has a judging unit that judges, on the basis of a charge-discharge state of the secondary battery, whether or not calculation of a current SOC of the secondary battery is possible; and a charge controlling unit that, when judged that the calculation of the current SOC of the secondary battery is not possible by the judging unit, charges the secondary battery up to a predetermined fully charged state.