The utility model discloses a weightless feeding machine, which comprises a storage vat, a feeding hopper, a stirring device, a driving device, a feeding screw, a material level inductor and a load sensor, wherein the storage vat is cylindrical; the stirring device is arranged at the bottom part of the storage vat; the stirring device comprises a cone rotating shaft and a plurality of scrapers which are arranged around the bottom edge of the rotating shaft and extend along the radial direction; the conical tip of rotating shaft faces upwards; one of the scrapers can completely cover up the outlet of the storage vat, and moreover, the scraper is provided with a position sensor. The weightless feeding machine is simple in structure; the space use rate is greatly improved by the cylindrical storage vat, and moreover, the material supply can be kept constant; as the scraper of the weightless feeding machine is provided with the position sensor, the accuracy of the material supply is further improved. The weightless feeding machine is suitable for being applied to equipment, such as plasticator; through the improvements, the working efficiency of the plasticator can be further improved.