Abstract: A dust discharging apparatus suitable for use in a dust collector, which comprises series-connected upper and lower dust shoot chambers, each having a swingable discharging valve device to close and open its ceiling opening. In order to prevent dust coating on the seal members of the swingable valves and the wear of same, the swingable valve device uses a downstream-convergent throttle ring, a swingable concave pan-like valve and an upstream divergent bucket fixed to the concave plate. The upper chamber has an exhaust pipe to communicate with the dust hopper, and a suction pipe to permit the chamber to open to the surrounding atmosphere to prevent dust backflow when transferring the dust from the dust hopper to the upper chamber and then from the upper to lower chamber.