Provided is a method for producing a processed food which is produced by continuously heating/molding a fluid raw material containing a protein, a lipid, and water. A method for heating a material to be heated continuously by an internal heating system while moving the material in a tube comprising: (a) arranging the tube vertically or substantially vertically (a tilt of not greater than 15°) and heating/molding a mixture while feeding the mixture upward from a bottom in the tube and/or (b) heating/molding the mixture while rotating the tube around a rotation axis, the rotation axis being a center line in a length direction of the tube. The internal heating system is preferably microwave heating, Joule heating, or high-frequency heating. The method for producing a processed protein food employs the heating/molding method for production of a processed protein food wherein a material to be heated, which is a fluid mixture containing a protein, a lipid, and water, is molded by thermally coagulating the mixture continuously by an internal heating system while moving the mixture in a tube.