An optical element including a first groove extending from first end of the outer peripheral face in an optical axis direction towards second end, and a second groove connected to the first groove and extending from second end of the outer peripheral face in the optical axis direction towards first end; and a position-adjusting concave part which is between the first and second grooves and adjusts positions by adjusting member in the optical axis direction, a revolving direction about the optical axis, a width direction of first and second grooves, which is orthogonal to the optical axis, and in a synthesized direction that is a combination of at least two of those directions, wherein the optical element is molded by using only a first molding die for molding a part on the first groove side and a second molding die for molding a part on the second groove side.