The main purposes of this study were to lessen the deformities in the machined surface, to make the crystal grains on the machined surface appear, and to apply this machining at the micrometer level instead of at the nanometer level. The present study targets the development of a polishing technique that uses a photocatalyst and a luminous dye (Cathilon Brilliant Flavine; hereafter referred to as cathilon) excited by an ultraviolet ray. Nickel (hereafter referred to as Ni) was polished chemically and mechanically at the sub-micrometer level under an ultraviolet-ray irradiation. Measurements clarified that TiO2 of 0.1 μm grain size mechanically polished the Ni, and cathilon chemically polished Ni. A flat surface was attained on the Ni by chemical and mechanical polishing using both the TiO2 and cathilon, when they were irradiated by an ultraviolet ray. Further measurements indicated that the corrosion of Ni surface became large under an ultraviolet-ray excitation. The eroded trace was large when cathilon is rich. Though much TiO2 tends to roughen Ni surface, the flat surface was obtained in the case of much TiO2 and much cathilon due to both equivalent influences.