In order to obtain a radiation measurement system in which a shield is reduced in size to achieve reduction in cost and missing measurement is not present in the whole measurement range, and which is good in stability and responsiveness, a radiation detector which is low in measurement range of radiation is arranged in a sample vessel in which a sample gas serving as a radiation measurement object is made to flow; a radiation detector, which is high in measurement range having a measurement range that follows the radiation detector which is low in measurement range of radiation, is arranged outside the sample vessel; and the sample vessel and a plurality of the radiation detectors are surrounded by a shield to shield from environmental radiation.