To provide a method for suppressing corrosion of glass to be in contact with a liquid material containing fluoride ions or a condensate of gas vaporized therefrom, without adding an alkaline substance, and further without imposing restrictions on e.g. the temperature, the pH, the fluoride ion concentration and the water content. A method for suppressing corrosion of glass to be in contact with either one or both of a liquid material containing fluoride ions and a condensate of gas vaporized from the liquid material, wherein the liquid material contains a powder containing silicon dioxide, and the silicon dioxide is contained in a molar ratio of one or more times to the fluoride ions.