The enhancement of the growth rate of Al₂O₃ has been observed during plasma anodization accompanied by optical excitation with low-power visible argon-ion laser light. The increase of the current efficiency with the laser light is approximately 20% of that without. And this enhancement of the oxide growth rate is considered to arise from promoting the generation rate of atomic oxygens, which contribute to the anodization as oxidizing species, in the plasma sheath near the specimen and/or on the specimen surface irradiated by the laser light. Although most of atomic oxygens are regarded to be generated by the dissociation of molecular oxygens colliding with plasma electrons, the laser excitation might help the cumulative dissociation of molecular oxygens.