To provide a manufacturing method of a high-density, small-lump raw material for iron which is automatically cut of and charged without causing bridging in a furnace-top hopper in iron making or casting operation.

Only steel pieces of ≥3 mm thick which are by-product in a steel mill are shredded by a shredder in advance to manufacture small pieces of 100-200 mm square. The small pieces are charged in the shredder by 10-30% to the steel plates of ≤3 mm thick as by-product to manufacture high-density, small-lump and round steelmaking raw materials.