Provided is a gel-forming agent that is easy to prepare and has all the properties including high safety for the living body and the environment, satisfactory gel-forming capability, comfortable feeling upon use, and good handleability. The gel-forming agent includes a lecithin, and a polyglycerol fatty acid ester in an amount of from 30 to 150 parts by weight per 100 parts by weight of the lecithin. The polyglycerol fatty acid ester has a fatty acid residue having 14 or less carbon atoms, has an HLB of 15 or more as determined based on an organic conceptual diagram, and has a degree of glycerol polymerization of from 8 to 40.