Several studies in the author's former laboratory at Kyoto University, have been reviewed on the dissolution–precipitation reactions on the electrodes in the lead acid battery. At the discharges of β-PbO 2 in the positive electrode and Pb in the negative electrode, PbSO 4 deposited on both electrode surfaces through the large supersaturation of Pb 2+ ion. Thus, the discharge reactions of the positive and the negative electrodes proceeded smoothly, and the largest crystal size of PbSO 4 was obtained in 0.5–1.0 M H 2SO 4 with the largest Pb 2+ ion concentration on the surface. The size of its PbSO 4 crystals became smaller at a higher current discharge through the formation of many of nuclei on the electrode surface. On the other hand, the charge reactions, which are the anodic oxidation of PbSO 4 at the positive electrode and the cathodic reduction of PbSO 4 at the negative electrode, did not proceed in the same way as the discharge reactions, because PbSO 4 is a large ionic crystal without electronic or ionic conductivities and its solubility is very low in sulfuric acid solutions. The reaction site is considered to be the interface between β-PbO 2 of the positive active material, or Pb of the negative active material, and PbSO 4. At such an interface, Pb 2+ ions can be adequately supplied from the PbSO 4 crystal, and a charge-transfer reaction can occur on β-PbO 2 or Pb. The reaction rate depends on the electrochemical kinetics parameters, e.g., exchange charge-transfer rate, real area of the interface between PbO 2 or Pb and PbSO 4, and the mass-transfer in the narrow gap can be assumed to be like that of a thin layer cell. For the oxidation of PbSO 4 to ß-PbO 2, the charge-transfer process was the rate-determining step. For the reduction of PbSO 4 to Pb, the mass-transfer process was the rate-determining step. For both processes, it was concluded that a large crystal size of PbSO 4 gives a smaller current because of the smaller reaction site area per unit volume.