The invention discloses a dry material feeding device for a mixing machine. The dry material feeding device can improve stability in the feeding process. The dry material feeding device comprises a packing auger feeder. A conveying packing auger in the packing auger feeder comprises a rotating shaft and a packing auger blade. The packing auger blade includes multiple adjacent piece-shaped auger blades arranged independently and a section of continuous auger blade. The multiple independently-arranged piece-shaped auger blades are sequentially arranged at the discharging end of the packing auger feeder, and the rest of the section of the rotating shaft is provided with the continuous auger blade and is located at the feeding end of the packing auger feeder.