Abstract: The present invention relates to a method of producing a mold material used for obtaining a mold for casting metals such as Zn, Al and the like or molding resins. In the method, the short fibers having an aspect ratio of 30 to 300 and obtained by cutting ferritic stainless steel long fibers having a width of 100 .mu.m or less, ferritic stainless steel powder and at least one of Cu powder and Cu alloy powder are used as raw materials. The raw materials are blended to obtain a material mixture which is then compressed under pressure in a Cold Isostatic Press process. The thus obtained compressed product is sintered in a vacuum atmosphere. The sintered material is held in an atmosphere of nitrogen gas or decomposed ammonia gas so that 0.3 to 1.2 wt % of nitrogen is added to the stainless steel in the sintered material. The thus obtained mold material has a hardness of HMV 250 to 500.