An optical pickup apparatus for conducting recording and/or reproducing information
of an optical information recording medium, comprises a light source; a converging
optical system having an objective lens; and a photo-detector. The converging optical
system comprises a plastic lens and a spherical aberration deviation correcting
element to correct deviation of a spherical aberration of the converging optical
system. A numerical aperture of the objective lens at an image-side is 0.65 or more.
