A more inexpensive fluorescence measurement method and fluorescence measurement device that are structured more simply and can measure an amount of fluorescence using an extremely small sample. The fluorescence measurement device used is provided with: an opaque measurement box into which a microtube is loaded a container support part that is disposed inside the measurement box and supports the microtube vertically an excitation light source that is disposed inside the measurement box and provided with a light source that shines excitation light horizontally onto a side wall surface of the loaded microtube and a fluorescence detection unit that is provided in the top of the measurement box, above the loaded microtube, and measures the amount of fluorescence, in a specific wavelength region, from a target sample. A microtube filled with a target liquid sample is loaded into the measurement box excitation light having a specific peak wavelength is shined horizontally on a side surface of the microtube, which is uncapped and the specific-wavelength-region fluorescence detection unit measures the amount of fluorescence from the target liquid sample excited both by light distributed throughout the target liquid in the tube, with the side wall surface of the microtube serving as a waveguide for the excitation light, and by leaked light from said side wall surface.Linvention concerne un procédé et un dispositif de mesure de la fluorescence peu coûteux, qui présentent une structure simplifiée et permettent de mesurer la quantité de fluorescence au moyen dun échantillon extrêmement petit. Le dispositif de mesure de la fluorescence comprend: une boîte de mesure opaque dans laquelle un microtube est chargé une partie de support de contenant, qui est placée à lintérieur de la boîte de mesure et maintient le microtube verticalement une source de lumière dexcitation, placée à lintérieur de la boîte de mesure et qui est pourvue dune source lumineuse émettant une lumière dexcitatio
