Examining device for examining inner walls (4, 6) of a hollow body, in particular a cylinder bore in an engine block, having - a holding means for holding the hollow body, - a rod-shaped camera device which is designed to record an image transversely with respect to a longitudinal axis of the rod-shaped camera device, - an adjustment means for moving the camera device into and out of the hollow body, - an illumination means for illuminating the inner walls (4, 6) of the hollow body, - electronic control and evaluation means which are designed to control the camera device for recording a panoramic image around the longitudinal axis of the rod-shaped camera device, and to determine from image data recorded by the camera device surface properties of the inner walls (4, 6), and - a diameter determination means for determining an inner diameter of a cavity (3, 5) of the hollow body, wherein the control and evaluation means are designed to determine the inner diameter of the cavity (3, 5) from measurement information of the diameter determination means, characterised in that - the diameter determination means has a light source which is provided in addition to the illumination device to emit a light beam onto inner walls (4, 6) of the cavity (3, 5), and also has optical measuring means which are provided in addition to the camera device to detect light coming from the inner walls (4, 6) of the cavity (3, 5), - that the illumination device comprises a grazing light illumination device which is arranged so that emission directions of the grazing light illumination device, in which it illuminates inner walls (4, 6) during operation, are transverse with respect to receiving directions, from which the camera device receives light from the illuminated inner walls (4, 6), wherein an angle between the emission directions and the receiving directions is between 45° and 135° and - that the grazing light illumination device is arranged so that it is located outside of the hollow body when the camera device has been moved into the hollow body. - a holding means for holding the hollow body, - a rod-shaped camera device which is designed to record an image transversely with respect to a longitudinal axis of the rod-shaped camera device, - an adjustment means for moving the camera device into and out of the hollow body, - an illumination means for illuminating the inner walls (4, 6) of the hollow body, - electronic control and evaluation means which are designed to control the camera device for recording a panoramic image around the longitudinal axis of the rod-shaped camera device, and to determine from image data recorded by the camera device surface properties of the inner walls (4, 6), and - a diameter determination means for determining an inner diameter of a cavity (3, 5) of the hollow body, - the diameter determination means has a light source which is provided in addition to the illumination device to emit a light beam onto inner walls (4, 6) of the cavity (3, 5), and also has optical measuring means which are provided in addition to the camera device to detect light coming from the inner walls (4, 6) of the cavity (3, 5), - that the illumination device comprises a grazing light illumination device which is arranged so that emission directions of the grazing light illumination device, in which it illuminates inner walls (4, 6) during operation, are transverse with respect to receiving directions, from which the camera device receives light from the illuminated inner walls (4, 6), wherein an angle between the emission directions and the receiving directions is between 45° and 135° and - that the grazing light illumination device is arranged so that it is located outside of the hollow body when the camera device has been moved into the hollow body.