To provide a method for coating an object such as the lenses of a pair of spectacles, the frame of a pair of spectacles, or a portable telephone with silver/titanium oxide at a high degree of adhesion.

In the coating method for silver/titanium oxide, the object to be coated is prepared. Next, the surface of the object is washed with the first treatment liquid. Next, after the first treatment liquid is dried, the second treatment liquid is sprayed or applied on at least a part of the surface of the object, or at least the part of the object is immersed in the second treatment liquid to perform coating pretreatment at a prescribed temperature. Finally, a silver/titanium oxide aqueous solution is sprayed or applied on the part subjected to the coating pretreatment, or the object is immersed in the silver/titanium oxide aqueous solution to coat the part or the whole of the object with the silver/titanium oxide. The second treatment liquid is preferably an aqueous solution containing an amino acid, mineral powder, metal powder, a salt, and useful microorganisms.