A fixing device for fixing a longitudinally extended element, having a fixing sleeve that surrounds a lumen extended in an axial direction for receiving the longitudinally extended element, the fixing sleeve having an inner side defining the lumen and an outer side facing away from the inner side, the fixing sleeve being embodied for fixing the fixing sleeve on the longitudinally extended element to be subjected to compression in the radial direction of the fixing sleeve by means of the at least one fixing element. The fixing device has an indicator device that is embodied to visually indicate when a force applied to the fixing sleeve by means of the at least one fixing element for compressing the fixing sleeve attains or exceeds a threshold.