The etch pit growth behavior in aluminum foils for electrolytic capacitors during initial DC etching in hydrochloric acid is important in achieving high capacitance, but the relationship between the number of initial pits and pit growth has not been established.In this study, three kinds of foils with different number of initial pits were used. Pit size and pit growth rates were measured for each foil. The pit growth rates were measured by triangle waves, and the pit structures were observed by SEM images of oxide film replicas. The changes in pit size corresponded exactly to a triangle wave of 2Hz at electrolyte temperatures from 70 to 90°C. The pit growth rates for the three kinds of foils were nearly equal at the same electrolyte temperature, and were not influenced by the number of initial pits. The difference in the number of initial pits only affected the pit size.