To provide processed reject chip recirculating device of a saw-dust manufacturing machine contributing to the manufacture of saw-dust as an acceptable product by preventing processed reject chips from being included into saw-dust as a product and raising the yield of material by reprocessing.

The saw-dust manufacturing machine 5 manufactures the saw-dust of a specified size by cutting a wood conveyed by a conveyor 1 with the help of a receiving blade 3 and a rotary cutting blade 4, In addition, this machine 5 comprises a hopper 6 which is provided so as to cover at least the extent from one end part 2 of the conveyor 1 up to the blade 3 side of the saw-dust manufacturing machine 5 from below; a duct 7a connected with the lower part of the hopper 6; a fan 8 which sucks the processed chip reject falling inside the hopper 6, through the duct 7a; a duct 7b connected with the discharge side of the fan 8; and a cyclone 9 whose outlet side is positioned above the conveyor 1 by connecting the cyclone 9 with the duct 7b.