PURPOSE: To eliminate any adjustment preventing a device from being affected by noise outside so as to enable the accuracy in control to be improved by making use of pulse as a feed-back signal from measuring devices allowing data in the feed-back system to be processed by a digital system.

CONSTITUTION: The weight of delivery is detected in a form of pulse per an unit weight allowing the pulse to be counted and processed by a digital system. This enables an average weight delivered per a time width Δt for sampling to be computed. A motor 3 to drive a paddle 2 is controlled so that the above said average weight obtained is to be the stated set weight. This allows circuits in the digital system to be employed in a feed-back system where the weight delivered is controlled by the peddle drive. Accordingly, this configuration enables the device to be controlled stably with a constant gain provided over all the ranges, for which delivery can be set, permitting measuring signals to be well noiseproof. Simultaneously, this configuration always allows the average delivery per the time width Δt for sampling to be computed restraining delivery of raw materials from being fluctuated.