A container crane includes a movable trolley and a load-carrying frame pendantly connected to the trolley and comprised of a spreader and a head block, for transfer of a container from or to a transport vehicle. Plural optical detectors are mounted on the trolley for identifying longitudinal and transversal edges of the head block or spreader and the transport vehicle. Operatively connected to the detectors is a processing device for determining a spatial position of the edges and calculating a position of longitudinal and transversal center lines of the head block or spreader and the transport vehicle and their spatial positions in relation to one another. In this way a possible offset of the center lines of the head block or spreader with regard to those of the transport vehicle in longitudinal and transversal directions as well as a rotation angle of the center lines can be determined, whereby a detected offset or rotation angle is compensated by displacing the spreader relative to the head block.