An optical pickup device includes: a laser source for emitting, to an
optical disk, a laser beam having a wavelength .lamda.1 and a laser beam
having a wavelength .lamda.2, which is longer than the wavelength
.lamda.1; a light receiver, for receiving laser beams that are reflected
by the optical disk; a beam splitter, for directing, to the light
receiver, the laser beams reflected by the optical disk; and an
astigmatism generation element, located between the beam splitter and the
light receiver, for generating the laser beams to be used for focusing
control, by designating as the front of the light receiver a focal point
on one of the intersecting cross sections that include the light axes of
the laser beams, and by designating as the rear of the light receiver, a
focal point on the other cross section, wherein the astigmatism
generation element is an optical element, which is like a Fresnel lens,
whose step depth is substantially a natural number times either the
wavelength .lamda.1 or the wavelength .lamda.2.