An extrusion method capable of performing extrusion by means of an extrusion die that can improve oxidation resistance while maintaining the excellent performance of titanium sintered body is provided. The present invention is directed to an extrusion method in which an extrusion material F is extruded through an extrusion hole 33 of a main die body 31. A main die body 31 is prepared, wherein the main die body 31 is constituted by surface-coated cermet material 1 containing cermet base material 11 formed of a sintered body including at least one or more titanium compounds selected from the group consisting of titanium carbide, titanium nitride, and titanium carbonitride as a main component, and an oxidation resistant film 12 formed on a section on the cermet base material 11 corresponding to at least an inner peripheral surface of the extrusion hole and formed of a complex oxide containing titanium. The extrusion die is preheated to a temperature of 420 to 520° C. before initiating the extrusion.