A reflective-type soft X-ray microscope includes an image-focusing optical system including a concave mirror and a convex mirror, an illumination optical system that has a light source, a filter, and a focusing optical element for transmitting an illumination light beam, and a stage mechanism that carries and moves a sample under observation. In the reflective-type soft X-ray microscope, the concave mirror has at least one opening part for transmitting the illuminating light beam that illuminates the sample, and a reflected image of the sample is focused on a soft X-ray image detector by the image-focusing optical system.