Disclosed is an optical head, which comprises a semiconductor laser, a collimator lens for converting a beam emitted from the semiconductor laser light into parallel beam, a lens frame holding the collimator lens, a beam shaping prism for shaping the parallel beam passing through the collimator lens from an elliptic section into a circular section, an objective lens for converging the parallel beam passing through the beam shaping device on an optical recording medium formed with a track, and a photodetector for detecting a reflected light or transmitted light from an optical disk. The collimator lens is adhesively fixed to the lens frame at two positions opposed to one another along a radial direction corresponding to the minor axis direction of the cross section of the incoming parallel beam into the beam shaping prism. The optical head can suppress the displacement of detected-light spots in an photodetector caused by the displacement of an optical axis due to change in ambient temperature.