The device relates to the signaling, to the pilot of a moving vehicle, for example an aircraft, of its lateral maneuvering margins taking into account obstacles placed in its maneuvering zone. This device determines, over the maneuvering zone of the moving vehicle, the contours of a first type of risk region that must be bypassed and those of two other types of risk region consisting of lateral margins surrounding the first type of risk region, of widths less than separation thresholds or their upper limit considered necessary for a lateral maneuver without space constraint and displays them for the pilot of the moving vehicle. The determination of the separation thresholds takes into account the bearing angle under which a point of the contour of a region of the first type is seen from the moving vehicle.