When a fully charged lead negative electrode stood for one month in 1.OM H2SO4 solution at a temperature of 298.15 K, it was passivated through so-called "sulfation" as indicated by a decrease in the redox peak currents on cyclic voltammograms. As a method of reactivating the passivated lead negative electrode, we proposed the electrochemical redox potentiodynamic method in the potential range from 0.6 V vs. she to the potential of oxygen evolution at a positive electrode. It is recognized that the activity of the passivated lead negative electrode recovered completely after several cycles of such electrochemical treatment.