The method of impregnation treatment for foods comprises impregnating the foods with a liquid component or a gas component by contacting the foods with the liquid component or the gas component after vacuum treatment or in the vacuum state and/or cooling the foods in contact with the liquid component. The method of impregnation treatment for foods of the present invention enables readily impregnating various kinds of foods with various liquid components or gas components. The invention also provides a vitamin C-containing egg and a pidan-like egg.