To supply an adhesive to a gap between a holding member and an optical member in the state that the position adjustment of the optical member to the holding member is performed.

The gap is formed between an emitting side lens 26 and a lens fixing frame 29 when the light exiting side lens 26 as an optical element is mounted on the lens fixing frame 29 as the holding member. This is achieved by preliminarily forming a groove on the lens fixing frame 29. After the completion of the position adjustment of the light exiting side lens 26 to the lens fixing frame 29, the adhesive G composed of an ultraviolet setting resin is injected into the formed gap, then the adhesive G is hardened by radiating the ultraviolet ray, thus the light exiting side lens 26 is fixed on the lens fixing frame 29.