To provide a method of manufacturing Mn added aluminum alloy extruded die material parts in which deterioration in external appearance due to the occurrence of coarsened crystal grains after heat treatment at the surface of the extruded die material can be prevented.

After an Mn added aluminum alloy extruded die material is subjected, if necessary, to an annealing step, stretch forming is performed. At the recrystallization resultant from subsequent heat treatment such as solution heat treatment, crystal grains are uniformly refined. Then the extruded die material is subjected to stretch leveling and to aging treatment.