An equipment and method for charging a secondary battery are provided to quickly and surely charge a secondary battery (secondary batteries) while preventing the secondary battery (batteries) from overcharging or insufficient charging. Special charging voltage E.sub.s is applied to a secondary battery for a predetermined time, and then the applied voltage is switched to equilibrium voltage E.sub.eq for establishing equilibrium cell potential of the secondary battery in its fully charged condition, wherein the special charging value E.sub.s is larger than the equilibrium value E.sub.eq. Electric current i is detected while application of the equilibrium voltage E.sub.eq. If the detected electric current i is larger than standard electric current J for finishing charging, the above detection and charging are repeated; otherwise, charge of the secondary battery 1 is halted.