into the first and third hopper 16 and 20 the cast blocks 6 smaller than the predetermined size are fed into the second hopper 18 the iron pieces received by the hopper 16 18 and 20 are weighed and carried toward the supplying conveyer 28 by the weighing conveyers 22 24 and 26 respectively then the iron pieces received by the supplying conveyer 28 are successively delivered to the barrel 32 a through the supplying shoot 30 in the order of the iron scraps 4 the iron blocks 6 and the iron scraps 4 the iron pieces loaded in the barrel 32 a are pressed by a piston 32 b connected to a cylinder 32 c to thereby produce a metal feedstock then the resultant metal feedstock is ejected from the press 32 by the ejecting device 34 to describe in detail with reference to fig4 a predetermined amount of iron blocks 6 iron scraps 4 and iron scraps 4 are stacked one above the other with the iron blocks 6 intervening between the iron scraps 4 by pressing the layered iron pieces by the press 32 a sandwich structured metal feedstock 36 as shown in fig5 is formed this feedstock 36 is heavy enough to fall without flying up by the blast.