Optical waveguide paths to observe a sample on a sample holder from a plurality of directions while guiding an image of light in each direction which is emitted out of the sample toward a direction of a two dimensional detector via a main imaging lens include an optical waveguide path which never receives the light directly from the sample. The optical waveguide path which never receives the light directly from the sample forms an image of the sample within a substantial focus range of the main imaging lens, and includes optical elements arranged such that a light beam after formation of the image proceeds toward a direction of the main imaging lens. Optical elements on at least one optical waveguide path are those for forming real images. Therefore, the main imaging lens images the sample and those real images in block on the two dimensional detector.