Provided is a method suited for mass-producing a filled feed or food product having a two-layered structure including an outer layer and an inner layer. The method is a method of producing a feed or food product in which an inner layer is encrusted with a gelled outer layer composition, the method including the steps of: preparing an outer layer composition feedstock by adding a secondary feedstock to a protein feedstock and/or a starch feedstock that forms a gel upon heating and then mixing by stirring, and preparing an inner layer composition that is encrusted with the outer layer composition extrusion molding with an extruder provided with a double nozzle so as to cover a surface of the inner layer composition while simultaneously gelling the outer layer composition feedstock by heat treatment and cutting a continuously extruded cylindrically shaped product to a fixed length with a shutter mechanism while simultaneously encrusting a cut surface with the gelled outer layer composition.
