There is provided an optical pickup including a light source, an objective lens configured to focus light from the light source onto one signal face of an optical disc, the optical disc including two or more signal faces, each of the signal faces having a groove formed therein, a photodetector configured to receive returning rays from the optical disc, the photodetector having a light receiving face divided into four light receiving regions by a dividing line that is substantially parallel to a track direction of the optical disc and by a dividing line that is substantially perpendicular to the track direction, and a shading unit disposed at an incident side of the photodetector and configured to block, of returning rays from a signal face other than the one signal face of the optical disc, at least a diffracted ray that is diffracted by the groove.