PURPOSE: To detect the change of the weight of a carried object so as to control the carriage speed with high accuracy by providing a fulcrum at the position where the center axis of an inlet crosses a carrying means, and detecting the whole weight of the conveyor body as the moment at the weight detection point.

CONSTITUTION: The conveyor body 1 has an inlet 3, which opens upward at its one end, and an outlet, which opens downward at the other end, and the conveyor body 1 is separated dynamically at the inlet 3 and the outlet 4 with front and rear devices. For the conveyor body 1, the center axis at the inlet 1 is supported rotatably at the fulcrum Q provided at the position where the center axis of the inlet 3 crosses a carrying means 2, and also it detects the weight as the moment at the weight detection point P. Hereby, it becomes possible to detect the weight without acting the force at the time of the carrying means 2 picking up the powder and grain A supplied from the inlet 3, as the moment, on the weight detection point P.