A light-conducting device for an endoscope for conducting observation light from a proximal end of the endoscope to a distal end of the endoscope includes a number of optical fibers. Each optical fiber includes a proximal end with a light inlet surface, which is provided for positioning on a proximal end of an endoscope, and a distal end with a light outlet surface, which is provided for positioning on a distal end of an endoscope. Each of the number of optical fibers including in a proximal region a first cross-section with a first surface area, and in a distal region a second cross-section with a second surface area. The first surface area is larger than the second surface area.