A fluorometric assay apparatus comprising: a LED light source configured with at least two types of excitation LED (152BL, 152UV) that have different principle wavelengths from each other and are disposed in a two dimensional array on a substrate; an imaging lens for imaging a subject; a single excitation filter provided between the LED light source and the subject, the single excitation filter transmitting each of principle wavelength components of the LED light source; wherein the at least two types of LED (152BL, 152UV) comprise a near ultraviolet LED and a blue LED; and the single excitation filter is a band pass filter that transmits light of a band from near ultraviolet to blue; and a single detection long pass filter provided between the imaging lens and the subject, further comprising a subject placement section for placing the subject, characterized in that the LED light source is configured by the two dimensional array disposed on the substrate such that the number of individual near ultraviolet LEDs per unit surface area increases as the separation distance from the subject placement section gets shorter, (i) by increasing the proportion of the near ultraviolet LEDs with respect to the blue LEDs within the two dimensional array of the LEDs according to the separation distance from the subject placement section, or (ii) by increasing the number of individual near ultraviolet LEDs in the vicinity of the subject placement section while the individual number of the blue LEDs is left unaltered. a LED light source configured with at least two types of excitation LED (152BL, 152UV) that have different principle wavelengths from each other and are disposed in a two dimensional array on a substrate; an imaging lens for imaging a subject; a single excitation filter provided between the LED light source and the subject, the single excitation filter transmitting each of principle wavelength components of the LED light source; wherein the at least two types of LED (152BL, 152UV) comprise a near ultraviolet LED and a blue LED; and the single excitation filter is a band pass filter that transmits light of a band from near ultraviolet to blue; and a single detection long pass filter provided between the imaging lens and the subject, further comprising a subject placement section for placing the subject, characterized in that the LED light source is configured by the two dimensional array disposed on the substrate such that the number of individual near ultraviolet LEDs per unit surface area increases as the separation distance from the subject placement section gets shorter, (i) by increasing the proportion of the near ultraviolet LEDs with respect to the blue LEDs within the two dimensional array of the LEDs according to the separation distance from the subject placement section, or (ii) by increasing the number of individual near ultraviolet LEDs in the vicinity of the subject placement section while the individual number of the blue LEDs is left unaltered. (i) by increasing the proportion of the near ultraviolet LEDs with respect to the blue LEDs within the two dimensional array of the LEDs according to the separation distance from the subject placement section, or (ii) by increasing the number of individual near ultraviolet LEDs in the vicinity of the subject placement section while the individual number of the blue LEDs is left unaltered.