A measuring mixer for use with either liquids or powders in which different supply systems supply different stock liquids or powders to a receiving container from supply containers. A continuously variable flow regulator is associated with each supply container. The cumulative weight of the receiving container is measured and compared with a target weight. Then a computation section calculates a desired flow rate based upon both the deviation from the target weight and a time variation thereof. This calculation is preferably done according to fuzzy inference. The desired flow rate is then used to control a selected one of the flow regulators so that the measurement is sequentially performed between supply systems. Optionally, the receiving container can be movable between the different supply systems.