An endoscope optics including a housing receiving an image-observation device and a tubular stem. The stem is secured to a distal end of the housing. An image transmitting device is mounted inside the stem. The image-observation device is aligned inside the housing with the image transmitting device regarding image position and image center. An insert element is used to adjust the image-observation device and includes an outer contour, which allows stationary affixation to the housing, and an inner, axially continuous borehole, which receives the image-observation device in geometrically interlocking manner. The relative position between the borehole and the outer-wall contour inside the insert element is determined by spatial coordinates ascertained for the particular endoscope optics and specifying the position at which to adjust the image-observation device inside the housing relative to the image transmitting device.