A lens position adjusting mechanism includes a lens, a lens attachment frame that includes a lens holding portion for holding the rim of the lens, and a holding case that sandwiches the lens attachment frame movably in a plane direction perpendicular to an optical axis of the lens. The lens attachment frame includes a shaft portion on the periphery of the lens holding portion, functioning as a fulcrum at a time when the lens attachment frame moves in the plane direction. The holding case includes a shaft supporting portion for supporting the shaft portion and frame guide grooves for sandwiching the lens attachment frame. The position of the lens is adjusted by operating a lug portion by fingers or the like with the shaft portion as a fulcrum. Then the adjusted position is fixed by injecting an adhesive into wedge spaces formed of opposing adhesion grooves.