Adjustment device for a top bow for a foldable roof of a vehicle, - with a roof material which merges at the front in the direction of travel into a top bow, - with two guide rails which, in the fitted state of the foldable roof, extend laterally along a roof opening, - wherein the top bow is mounted so as to be moveable in the guide rails laterally via links and carriages, - wherein, as the foldable roof opens, the top bow is first of all raised vertically and is then displaced along the guide rails counter to the direction of travel, - wherein at least one carriage has a locking device with respect to a first guide rail, and, when the foldable roof is closed, said locking device secures the top bow in a lowered position with respect to the guide rail, - wherein, when the foldable roof is open, the top bow is deposited on the folded-up foldable roof by means of links in the rear of the vehicle with its front edge pointing in the direction of travel, characterized - in that the top bow is moved from a closed position into a vertically raised position via four-bar linkage kinematics, and in that the four-bar linkage kinematics is formed from a front and a rear link (25, 35), - in that the vertical raising of the top bow and the movement of the top bow along the first guide rail takes place by means of a driver carriage which is moveable along the guide rail and is coupled to the front link via a driver, - in that the driver of the driver carriage engages in a slot in the front link, - in that, when the top bow is raised vertically, a locking hook of the front link is moved out of a recess in a front part of the first guide rail, - in that, when the foldable roof is open, the front edge of the top bow substantially points in the direction of travel. - with a roof material which merges at the front in the direction of travel into a top bow, - with two guide rails which, in the fitted state of the foldable roof, extend laterally along a roof opening, - wherein the top bow is mounted so as to be moveable in the guide rails laterally via links and carriages, - wherein, as the foldable roof opens, the top bow is first of all raised vertically and is then displaced along the guide rails counter to the direction of travel, - wherein at least one carriage has a locking device with respect to a first guide rail, and, when the foldable roof is closed, said locking device secures the top bow in a lowered position with respect to the guide rail, - wherein, when the foldable roof is open, the top bow is deposited on the folded-up foldable roof by means of links in the rear of the vehicle with its front edge pointing in the direction of travel, - in that the top bow is moved from a closed position into a vertically raised position via four-bar linkage kinematics, and in that the four-bar linkage kinematics is formed from a front and a rear link (25, 35), - in that the vertical raising of the top bow and the movement of the top bow along the first guide rail takes place by means of a driver carriage which is moveable along the guide rail and is coupled to the front link via a driver, - in that the driver of the driver carriage engages in a slot in the front link, - in that, when the top bow is raised vertically, a locking hook of the front link is moved out of a recess in a front part of the first guide rail, - in that, when the foldable roof is open, the front edge of the top bow substantially points in the direction of travel.