A paper money processing device is provided with: a storage unit for forming a storage space in which paper money is layered and stored; a conveyance mechanism for conveying paper money to the storage unit; and a movable piece capable of emerging and sinking the storage space, the movable piece being provided in a direction orthogonal to the conveyance direction of the paper money conveyed by the conveyance mechanism. Conveyance is stopped in a position where the trailing end part of the paper money to be conveyed to the storage unit by the conveyance mechanism is facing the moveable piece, the trailing end part of the paper money in a position facing the moveable piece is thereafter moved to the storage space side and the paper money is layered and stored in the storage space by the emerging/sinking operation of the movable piece.