To provide an optical pickup device that facilitates thin shape and low cost by tilt-sensing using light even if the device is structured for the use of a single light source and thereby dispensing with an externally attached tilt sensor.

A part of an optical flux from a light source 4 is diffracted by a diffraction element 10 and made incident on an objective lens 7 through a collimator lens 5; as a result, a part of the light-source light unused before can be utilized for tilt-detection, tilt is detected without lowering light utilizing efficiency, and by eliminating an externally attached tilt sensor, the number of parts is reduced and the optical pick up is made thin. In addition, as tilt detection light 13 is emitted to a position very close to the actual information detection light 12 through the objective lens 7, tilt detection is performed with high accuracy, and as the tilt detection light 13 is emitted nearly in a state of parallel beams, the beam diameter is large. Hence, stable tilt detection against noise, and the like is possible without being affected by the presence/ absence of pits, scratches or the like on the surface of an optical recording medium.