Highly ordered arrays of etched tunnel pits were formed using an Al foil pretexturing process. Shallow concaves formed by imprinting Al using a mold with ordered convexes led to the formation of tunnel pits, and generated an almost ideally ordered array of etched tunnel pits propagating along the (100) plane. The obtained ordered tunnel pits were straight and perpendicular to the surface. The present process will be useful for optimizing the surface area of the electrode for electrolytic capacitors.