An optical head is provided that increases the light utilization
efficiency and that can be adapted to high-speed recording and
double-layer disks. A beam-shaping lens that shapes an elliptical beam
emitted from a light source into a substantially circular beam has a pair
of cylindrical surfaces that are curved in the same direction. The
cylindrical surface that is closer to the light source is an aspherical
surface, and the cylindrical surface that is closer to the light source
is a spherical surface. Thus, an optical head is obtained, with which
aberrations can be kept low, even when the beam-shaping magnifying power
is about a factor 2.