PURPOSE: To drastically impart working strain and to improve Young's modulus by incorporating an easy-to-oxidizing, easy-to-nitriding or easy-to-carburizing element in advance the forming-working of an Fe-Cr ferritic steel, and subjecting it to reaction heat treatment.

CONSTITUTION: The powder of the Fe-Cr ferritic steel composition is subjected to the forming-work including an extruding-work having ≥3 extruding ratio and the secondary recrystallizing heat treatment. At this time, in advance the forming work, the easy-to-oxidizing element of Al, Ti, Mn, etc., or Cr is incorporated into the alloy powder and the heat treatment is applied in the oxidizing atmosphere. Or, the easy-to-nitrizing element of Zr, Ti, Al, etc., or Cr is incorporated into the alloy powder and the heat treatment is applied in the nitrizing atmosphere. Or, the easy-to-carburizing element of Zr, Ti, Ta, etc., or Cr is incorporated into the alloy powder and the heat treatment is applied in the carburizing atmosphere. The grains of oxide, nitride, carbide, etc., can finely be dispersed by this reaction-heat treatment and a high rigid material developed in <111> aggeregate structure is obtd.