Abstract: An optical pickup device, which reduces the size of an optical spot formed on an optical disk, and prevents the degradation of a tracking error signal due to coherent light from a layer adjacent a target recording/reproducing layer of the optical disk. The optical pickup device includes a light source emitting light at a designated wavelength; an object lens concentrating the light incident from the light source thereupon and forming an optical spot on an optical disk having multiple recording layers; and an optical detector receiving the light reflected by the optical disk and detecting a data signal and an error signal, wherein at least one diffraction pattern region partially diffracting or intercepting the light, emitted from the light source and being incident upon the object lens, and the light, reflected by optical disk and being incident upon the object lens, is formed on the object lens.