the side scattered light l 4 is reflected by the reflective component 20 reflective surface 201 disposed on the lateral side of the reaction area 2 and output in the light output surface direction lt 1ad step gt regarding the output light l 4 the amount of light is detected by the light detecting unit 5 optical detector 5 a that is the amount of scattered light due to the precipitated substance generated in association with the progression of the amplification reaction is detected it is also possible to detect the scattered light l 3 by light detecting unit not shown such as a ccd however it is also possible to prevent the passage of the scattered light l 3 by disposing a light blocking substance in the substrate 6 1 b when phosphor component 23 is present in substrate 6 lt 1ba step gt this step is the same as the above described lt 1aa step gt lt 1bb step gt this step is the same as the above described lt 1ab step gt lt 1bc step gt the side scattered light l 4 from the reaction area 2 is transmitted through the phosphor component 23 sidewall including a phosphor component phosphor component layer or the like to thereby become fluorescence light l 5 this light l 5 is reflected by the reflective component 20 reflective surface 201 disposed on the lateral side of the reaction area 2 and output in the light output surface direction.