An optical pickup includes a wave plate on an optical path to be followed by every light beam emitted from three light sources (with wavelengths λ1, λ2 and λ3, respectively) both on their way toward an optical disc and back from the disc toward a photodetector. The wave plate has two layers with different retardations and different optic axis directions. The sum of the retardations of the first and second layers is defined to be approximately 5/4λ1, 3/4λ2 and 1/2λ3 to the light beams with the wavelengths λ1, λ2 and λ3.