Abstract: A binder is provided for joining a plurality of objects together with a binding string. The binder includes a base member having a recess for receiving the objects. Structure for feeding the binding string is disposed behind the recess. A hook-shaped hand is provided for guiding the binding string around the objects and for causing a loose end of the binding string to turn back in a U shape while pressing the binding string against the objects to be bound, and for twisting the loose end of the binding string with another portion of the binding string to perform binding. The hook-shaped hand includes a slide base plate capable of moving backward and forward relative to the recess, a hook-shaped curved member rotatably coupled to the slide base plate and movable backward and forward in response to movement of the slide base plate, and a rotation mechanism for engaging and thereby rotating the hook-shaped curved member toward the recess in synchronized relation with forward movement of the slide base plate.