A light-conducting device for an endoscope to conduct illuminating light to the distal end of the endoscope including a curved, rigid portion with a predetermined spatial configuration, such that the curved, rigid portion is foreseen for positioning on a distal end of an endoscope, such that the curved, rigid portion has its rigid property at least either before insertion of the light-conducting device into an endoscope or before configuration of a direct or indirect mechanical connection of the light-conducting device with an inner shaft for an endoscope or before configuration of a direct or indirect mechanical connection of the light-conducting device with an outer shaft for an endoscope.