A method of manufacturing an optical element which obtains an optical element with a plastic lens portion by molding machining using a pair of molds (13, 15), wherein a cavity which is formed when the pair of molds are closed has a compression molding space and an annular injection molding space connected to the outer circumferential edge of the compression molding space, the method comprises: a compression molding step of casting a compression molding material into the compression molding space of the molds and closing the molds in an atmosphere equal to or higher than the glass transition temperature of the compression molding material to transfer the transfer surfaces of the molds to the compression molding material; and an injection molding step of injecting an injection molding material into the injection molding space in a state where the molds are closed and forming an injection molded portion at the outer circumferential edge of the compression molded compression molding material, and in the injection molding step, before the compression molding material reaches a temperature lower than the glass transition temperature, the injection of the injection molding material starts, wherein, in the injection molding step, the outer circumferential edge of the compression molding material is deformed by the injection of the injection molding material, wherein the compression molding space has an optical surface molding space which is defined between the lens transfer surfaces (21a, 23a) of the pair of molds, and an annular pushing compensation space which is connected to the outer circumferential edge of the optical surface molding space, and the injection molding space is connected to the outer circumferential edge of the pushing compensation space, and wherein the lens portion has a concave lens shape, wherein the optical surface molding space is a space for molding the lens portion of the optical element, the pushing compensation space is a space for molding an annular pushing compensation portion formed at the outer circumferential edge of the lens portion, and the injection molding space is a space for molding an edge portion formed at the outer circumferential edge of the pushing compensation portion, and wherein the pushing compensation portion has a first portion formed of the compression molding material and a second portion formed of the injection molding material, and a part of the interface between the first portion and the second portion has a shape protruding toward the optical axis (Ax) of the lens portion. a compression molding step of casting a compression molding material into the compression molding space of the molds and closing the molds in an atmosphere equal to or higher than the glass transition temperature of the compression molding material to transfer the transfer surfaces of the molds to the compression molding material; and an injection molding step of injecting an injection molding material into the injection molding space in a state where the molds are closed and forming an injection molded portion at the outer circumferential edge of the compression molded compression molding material, and in the injection molding step, before the compression molding material reaches a temperature lower than the glass transition temperature, the injection of the injection molding material starts, wherein, in the injection molding step, the outer circumferential edge of the compression molding material is deformed by the injection of the injection molding material, wherein the compression molding space has an optical surface molding space which is defined between the lens transfer surfaces (21a, 23a) of the pair of molds, and an annular pushing compensation space which is connected to the outer circumferential edge of the optical surface molding space, and the injection molding space is connected to the outer circumferential edge of the pushing compensation space, and wherein the lens portion has a concave lens shape, wherein the optical surface molding space is a space for molding the lens portion of the optical element, the pushing compensation space is a space for molding an annular pushing compensation portion formed at the outer circumferential edge of the lens portion, and the injection molding space is a space for molding an edge portion formed at the outer circumferential edge of the pushing compensation portion, and wherein the pushing compensation portion has a first portion formed of the compression molding material and a second portion formed of the injection molding material, and a part of the interface between the first portion and the second portion has a shape protruding toward the optical axis (Ax) of the lens portion.