An optical head for recording/reproducing signals to/from a high-density
multi-layer optical recording medium is provided, which is capable of
performing stable recording and reproducing with an aberration in each
layer being minimized even when the optical recording medium tilts. The
optical head includes a light source (1), an objective lens (7) for
focusing light emitted from the light source (1) on an optical recording
medium (8), and an objective lens tilting means (13) for correcting an
aberration that occurs when the optical recording medium (8) tilts. It is
configured so as to vary a tilted amount through which the objective lens
tilting means (13) tilts the objective lens according to information
concerning a tilt of the optical recording medium (8) and information
concerning a substrate thickness of the optical recording medium (8).