PURPOSE: A thickening agent that contains, as active ingredients, esters and/or salts from glycelol or polyglycerol, fatty acids of solid at room temperature and polybasic acids, thus having combinations of high safety, favorite feel on use and satisfactory thickening effect.

CONSTITUTION: The objective thickness agent contains, as active ingredients, at least one selected from esters and their salts from (A) glycerol polym-glycerol of 2W15 polymerization degree, (B) fatty acids, which is solid at room temperature such as stearic acid and (C) a polybasic acid such as carboxylic acids such as succinic acid or inorganic acid such as phosphoric acid. Since the resultant tickener is composed of substances which have been widely used as food additives, their safety is high, Further, the kinds of components A, B and C, esterification degree, neutralization degree or condensation degree are varied to enable a wide range of substance to have optimal thickening ability with good usability.