A tilt angle detection device and method which generates, as a first
push-pull signal, a difference between light reception signals
corresponding to two light receiving surfaces of one side of a
photodetector, which are divided along the track tangent direction;
generates, as a second push-pull signal, a difference between the light
reception signals corresponding to two light receiving surfaces of the
other side of the photodetector; and generates a tilt signal that
indicates a tilt angle defined by a normal on the recording surface of
the optical recording medium at a position of irradiation of the laser
beam and the optical axis of the laser beam in accordance to a difference
between amplitudes of the first and second push-pull signals.