To provide a paper sheet binder capable of depressing stacked paper sheets by a pressing means with a small drive torque by providing the pressing means in the vicinity of a scraping member.

This paper sheet binder comprises a receiver device which is movable between the stacking position and the binding position, introduces advancing securities into an impeller and abuts them on a scraping plate 31 to scrape and stack them, a sweeper device 30 which is provided in the vicinity of the scraping plate 31 and moves unbound bundle H to the binding position by pressing a center part on one end side of the unbound bundle in the vicinity of the scraping plate 31, a curving device for pressing and curving both sides on one end side of the unbound bundle H moved to the binding position by the sweeper device 30 in the direction opposite to the pressing direction of the sweeper device 30, and a heat-bonding device for winding and binding a strip-like member B around one end side of the unbound bundle curved by the curving device.