An optical pickup has a first optical system and a second optical system. The optical axis of the first optical system and the optical axis of the second optical system are inclined, for example, 45 degrees with respect to the reference plane, and are parallel to each other. A first objective lens and a second objective lens are arranged substantially side-by-side in a radial direction, and the center position of the second objective lens is slightly displaced from the reference plane in a tangential direction. The first optical system and the second optical system each have a flat-shaped beam splitter; this is used to produce astigmatism for acquiring a focus error signal by the astigmatic method.