PURPOSE: To produce a steel sintered body excellent in wear resistance, strength and toughness by specifying the compsn. constituted of C, Cr, Ni, Mo and Fe and regulating its relative density to high one.

CONSTITUTION: This steel sintered body is a one having a compsn. contg., by weight, 0.15 to 0.5% C, 8 to 11% Cr, 5 to 8% Ni, 1 to 2% Mo, and the balance Fe with inevitable impurities and having ≥95% relative density, and whose surface hardness is preferably regulated to ≥45 HRC by surface hardening by carburizing and quenching or carbo-nitriding or the like. This steel sintered body can be obtd. by blending metal powder or allay powder so as to regulate its compsn. to a prescribed one to form into a powdery mixture having about 3 to 40μm average grain size, subjecting this powdery mixture to direct press forming, kneading the same with a binder, subjecting it to injection molding, thereafter removing the binder and sintering the obtd. molded body. At this time, the sintering conditions are regulated so as to regulate the relative density to ≥95%. The steel sintered body having high density is subjected to hardening treatment to regulate the hardness only of the surface to high one and to increase its wear resistance, by which the sintered body free from hardening on the core part and having high toughness can be obtd.