PURPOSE: To produce a sintered material at relatively low temperatures that has a high density close to the true density, and is excellent in the mechanial properties including toughness, by heating an iron base sintered material to a temperature just above the Ac3 point, and immediately subjecting it to high velocity forging process.

CONSTITUTION: The iron base sintered material is prepared in such a way that powders of about 60W100wt% Fe as main constituent and about 0W40wt% at least one of C, Si, Ni, Cr, Co, W, Mo, V, Mn, Ti and Nb as additive elements and unavoidable impurities, or powders obtained from the former powders by alloying at least part of said former powders are mixed, molded and sintered. The sintered material is heated to a temperature in the range between its Ac3 and the Ac3 plus 50°C for 10W20min in a reducing gas such as H2 or the like or in an inert gas such as N2 or the like or in vacuo, and is then immediately subjected to high velocity forging process under a forging energy of about 1.0ton.m or more at a forging speed of about 6m/sec or more.