the optical pickup device according to the present invention , includes : a light emitting diode for emitting a light beam ; a collimating lens for collimating the light beam ; an objective lens for focusing the collimated light beam from the collimating lens onto a recording medium ; a beam splitter for splitting the light beam returned from the recording medium into two light beams ; a servo error signal detector for receiving one of the two light beams and detecting a servo error signal ; a diffracting element for diffracting the one of the two light beams from the beam splitter to direct the one of the two light beams toward the servo error signal detector ; and an optical waveguide element for receiving the other one of the two light beams and detecting a magneto - optical signal , the other one of the two light beams from the beam splitter being incident upon the optical waveguide element without passing through the diffracting element , wherein the beam splitter is disposed between the collimating lens and the diffracting element .