Abstract: A device for the accurate positioning of the LWL fiber ends of LWL components, particularly of LWL switches and plug connectors in which a support surface is provided with a guide slot arranged at right angles to the surface for receiving the support part of LWL fiber ends. The accurate positioning of the LWL fiber ends takes place by means of a sliding part which presses the LWL fiber ends by spring force against the support surface of the device and the boundary surface of the support part. The lengthwise positioning is made possible by contact of the fiber end faces against the stop surface of a spacer. Such devices are useful for the manufacture of LWL components, particularly of LWL switches and plug connectors in telephone engineering.