PURPOSE: To develop a soft magnetic material having high saturated magnetic flux density and excellent mechanical strength by applying Fe-Co alloy powders having specific compsn. to pressure molding, sintering it and furthermore subjecting said sintered body to a hot isostatic pressing treatment under specific conditions.

CONSTITUTION: Electrolytic iron powders, metallic Co powders and Fe-Co alloy powders are mixed and the mixed powders having the compsn. of 50wt.% Fe and 50wt.% Co are finally prepd. Suitable amt. of zinc stearate as a lubricant is added to said mixed powders and the powders are subjected to green compacting. Said molded body is heated to about 350W500°C to voltaile zinc stearate of the lubricant away, is thereafter sintered at the high temp. of about 1,400°C in a reducing atm., is successively applied to the hot isostatic pressing or hot pressing in the range of the temp. 200°C lower than said sintered temp. to the sintered temp. at ≥500kgf/cm2 pressure in a reducing atm. such as Ar., etc.