PURPOSE: To obtain the title lens having ready control of optical characteristics by hydrolyzing plural metal alkoxides to give porous gel, providing the surface of the porous gel with a pressed shape, eluting part of the components and heat-treating at high temperature.

CONSTITUTION: A mixed solution of plural metal alkoxides (e.g. silicon alkoxide and titanium alkoxide) in an alcohol is mixed with water and subjected to hydrolysis of alkoxides and condensation reaction to prepare porous gel plate 1 having the uniform distribution of a titanium component. Then, shapes 2 are formed by mechanical processing or photo-lithography to either surface of the porous gel plate 1. The porous gel is immersed in an aqueous solution of hydrochloric acid and the titanium component is partially dissolved to form a titanium concentration distribution from the surface to the inside. The gel is washed, dried, heat-treated in an oxygen atmosphere up to 500°C, then in a He gas atmosphere at 1,200-1,400°C high temperature in vitrifying process to give the title lens capable of compensating aberration of the spherical surface with the shapes 2 and refractive index distribution 8.