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Measurements of radon and thoron exhalation rates have been done using the radon and thoron exhalation rate measuring instrument adopting the accumulation method. We obtained the 111 data in the 40 sites of the 14 prefectures in Japan. The arithmetic average value of the radon and thoron exhalation rates by all 111 data were obtained to be 8.6 mBq⋅m−2⋅s−1 and 0.80 Bq⋅m−2⋅s−1, respectively, and we have reported the radon and thoron exhalation rates in relation to the geological features. The relation between the exhalation rate and geology was shown that the exhalation rate had an increasing tendency in order of basic rock, neutral rock and acidic rock. We made the nationwide exhalation‐rate map using the survey data of exhalation‐rate of radon and thoron and the geological distribution map.