An ITO electrode was coated with layers of TiO2 by using a sol-gel method. The coated electrodes were calcined to change pore and crystal structure of the TiO2 layer, For these electrodes, cyclic voltammetry and spectro-electrochemical measurements were carried out in the absence of a substrate and in the presence of ethyl viologen as a substrate, Significant differences in electrochemical properties were found between the calcined and uncalcined electrodes, When a negative potential was applied to the uncalcined electrode, Ti3+ was formed in its TiO2 layer The uncalcined electrode reduced irreversibly ethyl viologen while the calcined one did reversibly These behaviors are discussed on the basis of the porosity and electronic structure of the TiO2 layer.