An optical pickup projects laser beams having the first to the third wavelengths, in response to the type of a recording medium which is an object to which recording or reproduction is to be performed, and reflecting light from the recording medium is received by a light receiving element. In order to reduce the sizes of the optical pickup, light of the second and the third wavelengths is generated by a single dual-wavelength light source, and reflecting light of all the wavelengths is to be received by the single light receiving element. A hologram element giving different optical effects to light of each wavelength is arranged between the light irradiating means and the light receiving element. Thus, appropriate information recording and reproduction can be performed by using light of each wavelength. |