A powder feeding device includes a powder container, a feeding tank in communication with the powder container, a negative pressure room in communication with the feeding tank via a suction port communicating tube; an air suction device in communication with the negative pressure room via a negative pressure room communication tube; a suction port opening and closing unit that opens and closes the suction port communicating tube; a negative pressure room opening and closing unit that opens and closes of the negative pressure room communication tube; an output port opening and closing unit that opens and closes an output port of the feeding tank; and a controller that performs negative pressure generation control, powder supply control, and powder discharge control. Further, the controller simultaneously starts the negative pressure generation control and the powder discharge control.