Optical pickup device

An optical pickup device comprising:

• a phase difference plate for converting states of polarization of emergent light from a laser light source and return light from an optical recording medium, the phase difference plate oriented such that an azimuth thereof is set in a range of 50° to 60° with respect to laser light for irradiating the optical recording medium which is emitted from the laser light source;
• and
• a polarizing/separating element for separating the return light from an optical axis leading from the laser light source to the optical recording medium and for guiding the return light to a photodetector on the basis of the states of polarization of the emergent light and the return light,
• wherein the polarizing/separating element has a partially polarizing characteristic whereby both s linearly polarized light and p linearly polarized light whose polarization directions are oriented in mutually perpendicular directions are separated from the return light toward the photodetector while including the s polarized light and the p polarized light at a fixed ratio except zero respectively,
• wherein both a transmittance Ts with respect to the s polarized light and a diffraction rate Rs with respect to the s polarized light are set to substantially 0.3 or more, while both a transmittance Tp with respect to the p polarized light and a diffraction rate Rp with respect to the p polarized light are set to substantially 0.3 or more.