To reduce fraction defective by preventing seizure from arising on the surface of an aluminum extruded material and preventing the occurrence of corner cracks and a deterioration in dimensional accuracy of corner parts (the occurrence of shrinkage).

An aluminum extrusion die 1 is used in which a choke angle is formed on the bearing surface of a die hole, the choke angle 1 in a corner part 5 is formed larger than the choke angles 2, 3 in the flat parts 6, 6 on both sides of the corner part and the choke angle is continuously changed from the 1 to the 2, 3 in the vicinity (choke angle changing region 7) of the corner part.