The present invention relates to an optical pickup and an optical disc apparatus having a mounted optical pickup. The problems concerning wavefront aberrations such as coma aberration, astigmatism, and spherical aberration occur when beams of light are focused on an optical disc. JP-A No. 2000-40249 discloses a technique for reducing the wavefront aberrations of the light beams. In the technique of JP-A No. 2000-40249, wavefront aberrations are corrected by assigning a required phase difference to the light beams that pass through a liquid crystal element disposed in the optical path of an optical pickup.
JP-A No. 2002-140831 discloses another technique for reducing wavefront aberrations of the light beams. In the technique of JP-A No. 2002-140831, an aberration-correcting optical system for correcting coma aberration and spherical aberration is disposed in the optical path of an optical pickup.