To produce a quality stabilizing agent for cake, effective for preventing the degradation of quality caused by the addition of oil and fat and giving a cake having good pastry density and inner phase state by including a polyglycerol fatty acid ester as an essential component.

This stabilizing agent is produced by dispersing preferably 3-20 wt.% of a polyglycerol fatty acid ester containing a polyglycerol monofatty acid ester as a main component in water and/or edible oil and fat. Preferably the fatty acid of the polyglycerol fatty acid ester is composed mainly of 14-22C unsaturated fatty acids (e.g. oleic acid), the polyglycerol contains diglycerol as a main component and a cake is prepared by compounding the quality stabilizing agent for cake.