To perform an extrusion with an excellent shape stability by constituting a male die by providing a 2nd male die housing plural port holes distributively supply a billet metal uniformly to respective port holes of a 1st male die behind the 1st male die having plural port holes to supply the billet metal to a welding room uniformly.

An extruded material E is obtained by extruding a billet metal B from an annular forming clearance 11 formed with a female die 2 and a male die 3. The male die 3 is composed of a 1st male die component member 6 and a 2nd male die component member 7. The shape of a port 12 of the 1st male die component member 6 may be designed so that the billet metal B is uniformly and distributively supply to a welding chamber 5. The shape of a port 13 of the 2nd male die component member 7 may be designed so that the billet metal B is uniformly and distributively supplied to the port 12. Therefore, designing can be facilitated.