An integral type objective lens unit which has the first lens part used for the first wavelength light, and the second lens part used for the second wavelength light whose wavelength is different from the first wavelength, and in which the first lens part and the second lens part are arranged in adjoining manner, and the objective lens unit for the optical pick-up apparatus in which, on the optical surface of the first lens part and the optical surface of the second lens part, a common reflection prevention film adopted for the light having the first wavelength and the light having the second wavelength is provided.