An optical pick-up device according to the present invention is mounted to a recording and/or reproducing apparatus in which an optical recording medium is employed as a recording medium to write and/or read out information signals on the optical recording medium. By disposing a light-emitting and receiving unit such that the surface of the rectangular substrate is inclined relative to the optical axis of the objective lens, the recording and/or reproducing apparatus having a small thickness can be obtained. Additionally, a first light path-changing member is disposed underneath the objective lens along the optical axis thereof, and a second light path-changing member is provided for changing the light path of the light beam emitted from a light-emitting element such that the optical axis thereof is deflected in the direction normal to an optical axis of the light beam passing between the objective lens and the first light path-changing member such that the light-emitting and receiving unit and the second light path-changing member is disposed in the proximity of a peripheral portion of the objective lens whereby a compactness of the optical pick-up device can be achieved.