An inclination detection apparatus is provided which includes an optical system for collecting a beam emitted by a light source onto an information memory medium. The inclination detection apparatus further includes a light detector for generating a detection signal in accordance with a light amount of the beam reflected by the information memory medium, the light detector including a first light receiving section and a second light receiving section. In addition, the inclination detection apparatus includes a signal processing section for processing the detection signal. The signal processing section generates an inclination detection signal based on a difference between a first sum signal and a second sum signal, the first sum signal being based on a sum of a first light receiving section signal and a second light receiving section signal, the second sum signal being based on a sum of a third light receiving section signal and a fourth light receiving section signal. Moreover, the signal processing section generates a tracking error signal based on a difference between a fifth light receiving section signal and a sixth light receiving section signal.