For the purpose to study about the characteristics of the process of the corrosion-induced deterioration detected on surface of RC wall with mortar finish, RC wall specimens were electrified and measured the amount of the deteriorations as crack, delamination and spalling by hammer and visual examination periodically. From the results, in the case the cover thickness was small, the delamination increased with the progress of the rebar corrosion, which behavior were not liner but agogics. And in the case the cover thickness was large, the cracks along the rebar increased on mortar surface with the progress of the rebar corrosion.