To produce sintered and carburized products having excellent surface hardness by sintering injection molded goods made of the powder of an Fe alloy contg. specific small ratios of Mo, W or further Ni, then subjecting these goods to a carburization treatment.

One or two kinds of the powder of Mo and W are added at ≤3% in total to carbonyl iron powder or further, Ni is added in the form of carbonyl Ni powder at a ratio of ≤10% thereto and the powder mixture is kneaded together with an org. binder consisting essentially of polypropylene and wax and is pelletized. The pellets formed in such a manner are injection molded as raw materials into metal molds and thereafter, the molded goods are heated to degrease and remove the org. binder contained therein. In succession, the molded goods are sintered by heating to a high temp. in a nonoxidizing atmosphere and are then subjected to the carburization treatment by heating in a RX gas, by which the hard carbide of Mo, W, etc., is formed on the surfaces of the sintered products. The products are then subjected to an oil hardening and tempering treatment.