PURPOSE: To obtain a transparent whey protein gelatinous composition usable as a food, having thermostability and high safety without damaging nutritive value of whey protein.

CONSTITUTION: (1) A whey protein gelatinous composition comprises whey protein dissolved or dispersed into water or a buffer solution and poly-L-lysine or its salt. (2) The whey protein gelatinous composition is produced by dissolving or dispersing whey protein into water or a buffer solution to give a solution or dispersion and adding poly-L-lysine or its salt to the solution or dispersion. Since the whey protein gelatinous composition is produced under a mild condition not by thermal denaturation, characteristics of whey protein are not damaged, the component is thermostable, transparent and is usable for various uses as a food ingredient suitable for food processing because the composition comprises only substances having high safety in terms of food hygiene.