A banknote processing device includes a differentiating section that differentiates banknotes, a temporary holding section that temporarily stores the differentiated banknotes, banknote storage containers that store the banknotes, and a conveyance route that connects the differentiating section, the temporary holding section, and the banknote storage containers. The processing device is constructed so that when the banknotes stored in the temporary holding section are sent out and stored in the banknote storage containers based on differentiation results of the banknotes by the differentiating section, the banknotes are conveyed from the temporary holding section via the differentiating section, and are stored in any one of the banknote storage containers, or the banknotes are conveyed from the temporary holding section, via a route that does not go through the differentiating section, and are stored in a specific one of the banknote storage containers.