Optical pickup apparatus

An optical pickup apparatus comprising:

• light sources for emitting light rays having first, second and third wavelengths;
• an optical path coupling member for bringing light rays having said first to third wavelengths to be in a traveling direction in common;
• a light condensing member for condensing light from said optical path coupling member onto an optical information recording medium;
• a diffraction element for diffracting reflected light from said optical information recording medium;
• and
• a plurality of photodetectors for receiving diffracted light rays from said diffraction element, wherein
• said optical path coupling member aligns an optical axis directed to the light condensing member of the first wavelength light having a shortest wavelength with that of the third wavelength light having a longest wavelength, and
• said diffraction element condenses +2nd order diffracted light of the first wavelength light and +1st order diffracted light of the second wavelength light and third wavelength light into a first photodetector, and condenses the −2nd order diffracted light of the first wavelength light and −1st order diffracted light of the third wavelength light into a second photodetector, using ±2nd order diffracted light of the first wavelength light and ±1st order diffracted light of the second wavelength light and third wavelength light as signal light from said optical information recording medium.