An ultraviolet radiation detector 10, detecting an ultraviolet radiation transmitted through or reflected from a measurement sample 15 from a light beam including at least the ultraviolet radiation, is characterized by spectral means 19 for spectrally splitting the ultraviolet radiation from the light beam and photodetection means 20 for detecting the ultraviolet radiation spectrally split by the spectral means 19, the photodetection means 20 including a photoelectric surface detecting only the ultraviolet radiation and formed of an element selected from In, Ga, N, Al, O and Cs.