An optical pickup head for operating on an information recording medium includes a light source for emitting a light beam. A transparent base plate has opposite surfaces formed with a semitransparent film and a hologram respectively. The semitransparent film is exposed to the light beam emitted from the light source, and reflects a portion of the light beam emitted from the light source. The portion of the light beam which is reflected by the semitransparent film forms a forward light beam. A condenser optical system serves to focus the forward light beam on the information recording medium. The forward light beam is reflected at the information recording medium, and forms a backward light beam. The backward light beam successively passes through the condenser optical system, the semitransparent film, and the transparent base plate, and then reaches the hologram. The hologram generates a backward +1-order diffraction light beam from the backward light beam. A plurality of photodetectors serve to receive the +1-order diffraction light beam and to convert the received +1-order diffraction light beam into corresponding electric signals respectively.