A reflecting mirror and an optical bench are placed on an external jig provided with a mirror holding portion for maintaining the reflecting mirror, and then the reflecting mirror and the optical bench are bonded and fixed, thus obtaining an optical head. An adhesion reference plane for the reflecting mirror is no longer required in the optical bench, thus reducing the size and cost of the optical bench. The mounting precision is high and stable. Further, the reflecting mirror is bonded and fixed at the vicinities of the approximate centers of its two opposed side faces and therefore the variation in orientation of the reflecting mirror due to expansion or contraction of an adhesive is lessened, thus achieving a highly-reliable optical head excellent in environmental stability characteristics.