A combination weighing apparatus comprising: a distribution unit configured and arranged to radially distribute product material introduced from above; a plurality of conveying units arranged around a periphery of the distribution unit; and a plurality of weighing hoppers arranged around a periphery of the conveying units, and at least one of the conveying units having a trough having an inside edge positioned below the distribution unit and an outside edge positioned above the weighing hopper, characterised in that at least one of the conveying units have a plurality of spiral members (5A,5B) placed above a bottom surface of the trough with each of the spiral members (5A,5B) defining an external peripheral surface, the plurality of spiral members (5A,5B) being configured and arranged to be rotatably driven so that the plurality of spiral members (5A,5B) convey the product material supplied from the distribution unit in a vicinity of the inside edge of the trough, along the external peripheral surfaces toward a vicinity of the outside edge of the trough, the plurality of spiral members (5A,5B) being configured and arranged to stop movement of the product material on the external peripheral surfaces when the plurality of spiral members (5A,5B) are not being rotatably driven. a distribution unit configured and arranged to radially distribute product material introduced from above; a plurality of conveying units arranged around a periphery of the distribution unit; and a plurality of weighing hoppers arranged around a periphery of the conveying units, and at least one of the conveying units having a trough having an inside edge positioned below the distribution unit and an outside edge positioned above the weighing hopper, characterised in that a trough having an inside edge positioned below the distribution unit and an outside edge positioned above the weighing hopper, at least one of the conveying units have a plurality of spiral members (5A,5B) placed above a bottom surface of the trough with each of the spiral members (5A,5B) defining an external peripheral surface, the plurality of spiral members (5A,5B) being configured and arranged to be rotatably driven so that the plurality of spiral members (5A,5B) convey the product material supplied from the distribution unit in a vicinity of the inside edge of the trough, along the external peripheral surfaces toward a vicinity of the outside edge of the trough, the plurality of spiral members (5A,5B) being configured and arranged to stop movement of the product material on the external peripheral surfaces when the plurality of spiral members (5A,5B) are not being rotatably driven. the plurality of spiral members (5A,5B) being configured and arranged to be rotatably driven so that the plurality of spiral members (5A,5B) convey the product material supplied from the distribution unit in a vicinity of the inside edge of the trough, along the external peripheral surfaces toward a vicinity of the outside edge of the trough, the plurality of spiral members (5A,5B) being configured and arranged to stop movement of the product material on the external peripheral surfaces when the plurality of spiral members (5A,5B) are not being rotatably driven.