Optical axis adjusting screw

An optical axis adjusting screw adapted to adjust an irradiating direction of light emitted from a light source of a lamp unit disposed in a lamp chamber defined by a lamp body having an opening and a cover which closes the opening of the lamp body and formed of a resin through injection molding which employs a mold, the optical axis adjusting screw comprising:

• a shaft portion having a threaded portion which is screwed into the lamp unit or a bracket which holds the lamp unit and a support shaft portion which is to be rotatably supported on the lamp body;
• a gear portion which is connected to one end of the shaft portion and which is operated to rotate;
• and
• a plurality of elastic engagement portions which is connected to an outer circumferential surface of the shaft portion, which are displaced in a direction in which the plurality of the elastic engagement portions are spaced apart from the shaft portion as the plurality of the elastic engagement portions approach the gear portion from the shaft portion, which can be elastically deformed in a direction in which the plurality of the elastic engagement portions move away from or are brought into contact with the shaft portion, and which are brought into contact with an inner surface of the lamp body at distal end faces thereof when the support shaft portion is supported on the lamp body,
• wherein a parting line produced on the elastic engagement portions when molded by the mold is formed on an entire outer circumferential edge of outer surfaces or on an entire outer circumferential edge of inner surfaces of the elastic engagement portions.