The present invention provides an optical pickup in which the transmission diffraction efficiency of plural recording and/or reproducing light beams of different wavelengths, radiated from plural light sources, may be prevented from being lowered, and in which the transmission diffraction efficiency and the angle of diffraction are both optimized. The optical pickup includes an imaging unit composed of an objective lens and a set of diffraction section and adapted for condensing light beams from first to third light sources on optical recording mediums, and the set of diffraction section includes a first diffraction section which gives the transmission diffraction efficiency for order-one diffracted light or order-minus-one diffracted light higher than that for light of the other orders in case light beams of first, second and third wavelengths are transmitted therethrough, and a second diffraction section which gives the transmission diffraction efficiency for order-zero diffracted light higher than that for light of the other orders in case the light beam of the shortest wavelength and the light beam of the longest wavelength out of the first, second and third wavelengths are transmitted therethrough, and the transmission diffraction efficiency for order-one diffracted light or order-minus-one diffracted light higher than that for diffracted light of the other orders in case the remaining light beam is transmitted therethrough.