Abstract: A device for processing a medium includes: a conveyor for conveying the medium; an internal storage for storing the medium, the internal storage being disposed inside a body of the device and connected to the conveyor; an external storage for storing the medium, the external storage being disposed outside the body and connected to the conveyor; a temporary storage for storing the medium temporarily, the temporary storage being connected to the conveyor; and a controller for controlling the conveyer to perform at least one of collection processing and replenishment processing, the collection processing being processing of conveying the medium from the internal storage to the external storage via the temporary storage, the replenishment processing being processing of conveying the medium from the external storage to the internal storage via the temporary storage.