To obtain attaching structure for optical parts capable of reducing the number of parts and facilitating assembly and adjustment.

An almost semicylindrical female screw part 30 extended in the direction of the optical axis L of a semiconductor laser 14 is provided in a recessed state on the upper surface of a pedestal 28 integrally molded with a housing. A male screw part 34 engraved on the outer peripheral surface of a cylindrical holder 32 is screwed in the female screw part 30. A collimator lens 16 is fixed inside the holder 32 with adhesive, etc., and its optical axis is aligned with the optical axis L. By rotating the holder 32, the lens 16 is moved along the optical axis L, and focusing is completed. Since the female screw part 30 is semicylindrical and the holder 32 need not be screwed therein from the end, a coarse adjusting time is shortened.