An optical lens made of plastic includes an optically functioning part, a flange part and disposed around the optically functioning part. The flange part has an outer circumferential face having a cylindrical surface about a lens optical axis. A gate-removed part is located at the outer circumferential face as an outward-projecting quadratic surface. The gate-removed part is located between a virtual outer circumferential face and a plane passing through a tolerance limit on the lens optical axis side. The virtual outer circumferential face is defined when a residual gate part is cut along a cylindrical surface coaxial with the lens optical axis and having a radius identical to that of the outer circumferential face. The plane is set on the lens optical axis side when the residual gate part is removed by cutting the flange part.
