Abstract: This invention enables highly accurate sample analysis by analyzing energy spectra obtained using a radiation detector, even under a high dose-rate environment. In a radiation analysis method disclosed here, first, a spectrum of a sample (measured spectrum) is measured by a radiation detector (sample measurement step: S1). The measured spectrum is obtained for each of different setting conditions, where a plurality of scintillators having different sizes and a plurality of shields having different thicknesses are used, respectively. Next, similar measurement is performed on a reference source (reference source measurement step: S2). Next, from reference spectra thus obtained in S2, a background nuclide-originating component, which is a component originating from a background nuclide (137Cs) included in the measured spectra, is estimated (background nuclide-originating component estimation step: S3).