There is provided an optical pick-up used for recording data to and/or reproducing data from at least three types of optical discs having at least two different thicknesses of cover layers. The optical pick-up includes light sources and an objective lens. A thickness t1 of a first optical disc, a thickness t2 of a second optical disc, and a thickness t3 of a third optical disc satisfy a relationship t1≦t2 NA3. Further, a first light beam for the first optical disc is incident on the objective lens as a converging light beam, and the second and third light beams for the second and third optical discs are incident on the objective lens as diverging light beams, respectively. Given that magnification of the objective lens is m1 when the first optical disc is used, magnification of the objective lens is m2 when the second optical disc is used, and magnification of the objective lens is m3 when the first optical disc is used, following conditions are satisfied: m1>0, m3