Abstract: A fluorescence detection apparatus for differentiating an object containing a fluorescent substance by detecting fluorescence emitted by the fluorescent substance, which apparatus includes: an excitation light source which emits ultraviolet light that excites a fluorescent substance; a light detector for detecting fluorescence; and an optical guiding system consisting essentially of a single glass block of an angular columnar shape having: an incidence face located on a side of the glass block, through which the ultraviolet light enters; a reflection and emission face constituted by an inclined face, from which the incident ultraviolet light reflects toward the object, and through which florescence emitted from the object passes toward the light detector; and a detection face at the bottom of the glass block facing the object, through which the ultraviolet light exits and hits the object, and through which florescence emitted from the object enters, thereby allowing for reduction in the size of the apparatus,