In an endoscope having a proximal end area, a distal end area introducible into the body of a human being, a shaft extending in a longitudinal direction, and an optical device extending through the shaft in the longitudinal direction thereof and movable relative to the shaft, to enable particularly easy and safe handling of the optical device it is proposed that the optical device be fixable in axial direction relative to the shaft in a first position and in at least a second position differing from the first position.