To provide a powder discharging device capable of preventing any catch of powder without adhering powder to a contact surface of a damper with a simple structure even when powder is adhesive.

In the powder discharging device, upper and lower damper chambers with upper and lower alternately openable/closable dampers are arranged below a hopper, and the powder to be charged in the hopper is continuously discharged by alternately opening/closing the upper damper of the upper damper chamber and the lower damper of the lower damper chamber. The powder discharging device comprises a communication pipe which is connected to the upper damper chamber and communicated with the outside air, an inlet valve arranged in the communication pipe in an opening/closing manner, an operation detection means for detecting the operation of the upper damper of the upper damper chamber, and a valve opening/closing means for opening/closing the inlet valve by the operation detection means. The inlet valve is opened in synchronization with the start of the closing operation of the upper damper, and the outside air is introduced into the upper damper chamber by using the negative pressure generated in the upper damper chamber.