A method of manufacturing a microlens comprising the steps of: (a) applying a resist for an excimer laser, an ultraviolet exposure or an electron beam onto a surface, and carrying out an exposure with a light in an ultraviolet region or an electron beam and a development, so as to form a patterned resist; (b) heat treating the resist patterned at the step (a) to give a shape of a microlens; and (c) implanting an ion in a plurality of directions into at least a surface portion of the resist to which the shape of the microlens is given at the step (b), to obtain a microlens having a heat resistance.