To provide a method of manufacturing an optical lens for irradiating a recording layer of an optical disc.

This method comprises forming a photo-converging means on one surface of a substrate 1 made from an optical material by dry-etching using as an etching gas a mixed gas of a fluorocarbon gas and at least a gas selected from the group consisting of oxygen gas, Ar gas and He gas. For example, after forming a masking piece corresponding with the shape of an optical lens on the substrate made from an optical material, deforming the shape of the masking piece to shrink in its surface area by thermal treatment, transcribing a photo-converging means corresponding with the shape of the mask on the substrate by dry-etching to form a small hemisphere lens 4.