Binder mechanism having a basic housing, which can be fixed on a binder spine or binder cover, having at least two aligning pins (12', 12"), which are arranged on the basic housing at a defined distance from one another, having a swing-action arched element which can be pivoted to a delimited extent along a pivoting path, between a closed position and an open position, on the basic housing by means of a bearing crosspiece, about a bearing-crosspiece axis or by means of a carrying rail, about a carrying-rail axis and has at least two swing-action legs (18', 18") which are spaced apart from one another by the distance of the aligning pins (12', 12"), can be coupled to the latter in pairs, in the closed position, to form a closed ring and, in the open position, release an insertion gap for documents, and having an actuating lever which is mounted in a housing-mounted bearing such that it can be pivoted to a limited extent about a pivoting axis, running transversely to the axis of the bearing crosspiece or transversely to the carrying-rail axis and which acts on an angled portion of the bearing crosspiece or on the carrying rail, at a distance from the carrying-rail axis, counter to an opening-directed spring force, wherein complementary catch elements (32', 32"; 34', 34"), which are locked to one another in the closed position to counter pivoting of the swing-action arched element, are arranged at the free ends of at least one of the aligning pins (12', 12") and swing-action legs (18', 18"), said pins and legs supplementing one another in pairs, and wherein the swing-action arched element, at the beginning of an opening operation, can be moved, by way of its swing-action legs (18', 18") on a movement path relative to the aligning pins (12', 12"), this triggering an unlocking action into an intermediate position with the catch elements exposed, and wherein a control mechanism is provided, said control mechanism controlling the movement path and/or the pivoting path of the swing-action arched element relative to the basic housing and being designed such that during the closing operation, in the manner of sequential control, in a first phase it releases the pivoting path of the swing-action arched element, the movement path being delimited in the closing direction of the catch elements, until the swing-action arched element, with its at least one catch element, is passed into the intermediate position, and, in a second phase, it releases the movement path of the swing-action arched element from the intermediate position to the closed position until the pairs of catch elements are locked to one another, characterized in that the control mechanism has a control member which is arranged on the angled portion of the bearing crosspiece or on the carrying rail such that it cannot be displaced in the direction of the movement path and which, on the movement path between the closed position and intermediate position, under the action of an opening-directed force of a first spring element, butts against a housing-mounted closing stop, which delimits the pivoting path of the swing-action arched element, and, on the pivoting path between the open position and intermediate position, under the action of a force of a second spring element acting in the locking direction, butts against a housing-mounted opening stop, which delimits the movement path of the swing-action arched element.