PURPOSE: To make it possible to perform metering excellent in combination accuracy, by providing a valve for setting the supply amount of a substance to be metered to a supply hopper while providing a sensor, which detects the supply amount of the substance to be metered on a dispersing plate, in the vicinity of each discharge port of the supply hopper.

CONSTITUTION: A supply hopper 4 for receiving a substance to be metered from a feeder is provided above the dispersing plate 1 of a combination balance and the discharge port of the hopper 4 is formed into a bifurcated form in the longitudinal direction of the dispersing plate 1 while a valve for setting the supply amount of the substance to be metered is provided to the supply hopper 4. In addition, sensors T, T' for detecting the supply amount of the substance to be metered on the dispersing plate 1 are provided in the vicinity of each discharge port 14 of the supply hopper 4 and the opening and closing of the valve 13 is automatically performed on the basis of the outputs of the sensors T, T'.