PURPOSE: To obtain a lens for eyeglasses having high fashionableness and functionality, by heat-treating a glass containing silver halide added with a colorant under a temperature gradient, thereby varying the diameter of silver halide particles continuously.

CONSTITUTION: A glass containing silver halide added with a colorant is heat- treated under a temperature gradient to obtain an eyeglass lens having a photochromic gradient and containing silver halide particles having continuously varying diameter. A colorant having too high ultraviolet absorbance is unsuited for the purpose. Preferable examples of the colorant are Pr6O11, Nd2O3, Sm2O3, Ho2O3, Er2O3, CoO, NiO, etc. The photochromic gradient can be attained by covering a part of the glass containing silver halide added with the above colorant with a heat-insulating heat-resistant material, and heat-treating the partially covered glass.