A self-emulsifying composition contains: 70 to 90% by weight of at least one compound selected from the group consisting of ω3 polyunsaturated fatty acids and their pharmaceutically acceptable salts and esters; 0.5 to 6% by weight of water; 1 to 29% by weight of a polyoxyethylene sorbitan fatty acid ester as an emulsifier (optionally including a polyoxyl castor oil, and not including lecithin); and lecithin in an amount of 3 to 40 parts by weight in relation to 100 parts by weight of ω3 polyunsaturated fatty acids and the like. The self-emulsifying composition is excellent in self-emulsifying property, composition dispersibility, emulsion stability, and absorbability, is free from ethanol and polyhydric alcohols or only has such an alcohol added thereto at a reduced concentration, and is useful for foods and pharmaceuticals.