In an optics tube for an endoscope, a lens arrangement including at least one rod lens is received in the inside of the optics tube, wherein a sleeve is fixed on the at least one rod lens and at least partially encloses the rod lens, and wherein the sleeve is welded to the optics tube. The invention also relates to an endoscope having such an optics tube, and to a method for mounting at least one rod lens in the inside of an optics tube.
