A method for chemically sensitizing a silver halide photographic emulsion with a selenium compound is disclosed. The sensitizing method comprises the steps of preparing a dispersion of solid particles of a selenium compound in an aqueous medium by a process comprising the following steps of (1) dissolving a substantially water-insoluble organic selenium compound in a substantially water immiscible low-boiling organic solvent to prepare a selenium compound solution, (2) dispersing the selenium compound solution in water or an aqueous solution of a dispersing aid to form a oil-in-water type dispersion, and (3) removing the organic solvent from the oil-in-water type dispersion by stirring the dispersion under a decompressed condition to precipitate the selenium compound so as to form a dispersion of fine solid particles of the selenium compound having an average particle size of 10 nm to 3 .mu.m;adding the solid dispersion particles of the selenium compound to a silver halide emulsion, and ripening the silver halide emulsion in the presence of the solid dispersion particles of the selenium compound.