A method of manufacturing an optical axis adjusting screw comprising a shaft portion and an elastic engagement portion including a base end fixed to an outer circumferential surface of the shaft portion, a free end at an opposite side of the base end in an axial direction of the shaft portion, an opposed surface which is apart from the outer circumferential surface of the shaft portion and opposed to the outer circumferential surface of the shaft portion, and a distal end face which is formed at the free end and is substantially perpendicular to the axial direction of the shaft portion, the method comprising: injecting a resin into a mold, characterized in that the mold includes: right and left dies (51, 51), wherein a mating plane extending in a vertical direction is formed between the right and left dies (51, 51) in a condition in which the right and left dies (51, 51) mate to each other; and a slider which is movable in the vertical direction with respect to the right and left dies (51, 51); wherein a cavity (51a, 51b, 51c) for molding the adjusting screw and generally extending in a front-rear direction is formed in the condition in which the right and left dies (51, 51) mate to each other, wherein the each of the right and left dies (51, 51) includes a projecting portion projecting into said cavity, wherein a forming recess portion opened in the vertical direction is formed in either the slider or the projecting portion, and wherein an end wall surface is provided in an end part of the forming recess portion in the front-rear direction, and the end wall surface is substantially perpendicular to the front-rear direction and intersects with said mating plane between the right and left dies (51, 51) so that no parting line is generated at the distal end face. injecting a resin into a mold, characterized in that the mold includes: right and left dies (51, 51), wherein a mating plane extending in a vertical direction is formed between the right and left dies (51, 51) in a condition in which the right and left dies (51, 51) mate to each other; and a slider which is movable in the vertical direction with respect to the right and left dies (51, 51); right and left dies (51, 51), wherein a mating plane extending in a vertical direction is formed between the right and left dies (51, 51) in a condition in which the right and left dies (51, 51) mate to each other; and a slider which is movable in the vertical direction with respect to the right and left dies (51, 51); wherein a cavity (51a, 51b, 51c) for molding the adjusting screw and generally extending in a front-rear direction is formed in the condition in which the right and left dies (51, 51) mate to each other, wherein the each of the right and left dies (51, 51) includes a projecting portion projecting into said cavity, wherein a forming recess portion opened in the vertical direction is formed in either the slider or the projecting portion, and wherein an end wall surface is provided in an end part of the forming recess portion in the front-rear direction, and the end wall surface is substantially perpendicular to the front-rear direction and intersects with said mating plane between the right and left dies (51, 51) so that no parting line is generated at the distal end face.