PURPOSE: To produce bricks for the lining of metallurgical furnace having improved spalling resistance by heating a brick containing more than a specific amount of chromium oxide at a specific temperature and varying the oxygen partial pressure of the atmosphere, thereby forming micro-cracks in the brick.

CONSTITUTION: A brick containing ≥20% chromium oxide is heated at 600-1200°C and the oxygen partial pressure of the atmosphere is repeatedly varied, while keeping the above temperature, between two levels, i.e., the level A (≥10-3Torr) and the level B (≤10-10Torr), in such a manner as to pass the step from B to A twice or more. Microcracks are formed in the brick by this process to effectively suppress the generation of spalling and obtain a brick usable for the lining of a metallurgical furnace.