Iron oxide agglomerates incorporated with the carbonaceous material having a grain size within a range of about 10 to 30 mm are prepared upon production of reduced iron agglomerates. Then, the iron oxide agglomerates incorporated with the carbonaceous material were laid thinly at a laying density of less than 1.4 kg/m2/mm or lower on a hearth of a moving hearth furnace. Subsequently, the iron oxide agglomerates are heated rapidly such that the surface temperature of the iron oxide agglomerates reaches 1200.degree.C or higher within one-third of the retention period of time of the iron oxide agglomerates in the moving hearth furnace. Then, the iron oxide agglomerates are reduced till the metallization ratio thereof reaches 85% or higher to form reduced iron agglomerates and then the reduced iron agglomerates are discharged out of the moving hearth furnace. With the procedures, reduced iron agglomerates of a high average quality can be obtained at a high productivity.