A first image-forming optical system that receives a beam of light from an objective forms a first image forming point. The first image-forming optical system forms the beam of light into a first optical image at the first image-forming point and relays the first optical image. A second image-forming optical system is provided to form an image of a monitor near the first image-forming point, and the image is relayed by the first image-forming optical system. A third image-forming optical system is arranged in the first image-forming optical system to form a second image-forming point. The third image-forming optical system forms a second optical images at the second image-forming point and guide the optical image to an eyepiece lens.