A thickening composition which contains specific amounts of a metal salt-enclosing dextrin and a thickening polysaccharide and which has a good dispersibility raises the viscosity rapidly, and has an excellent thickening effect can be produced by the steps of obtaining the metal salt-enclosing dextrin by mixing, dissolving, and homogenizing a dextrin and a metal salt in water, followed by drying, and adding the metal salt-enclosing dextrin to the thickening polysaccharide followed by mixing or granulation. The thickening composition makes it possible to provide a thickening composition to which has a good dispersibility, raises the viscosity rapidly, and offers an improved thickening effect per unit mass in a wide variety of water-containing foods such as water, teas, refreshing beverages, dairy beverages, soups, and thick liquid foods.