The concentrations of mercury were compared in rice dusted with mercury-fungicides and in undusted rice. 1) The concentration of mercury in unhulled rice was 30 to 35 μg% and that in polished rice was about 20 μg% (undusted rice). 2) There was a distinct increment of mercury content in rice by dusting of the mercuryfungicides, that is 55 μg% in unhulled and 30 μg% in polished rice dusted at flower primordia stage, and 90 μg% and 59 μg% in rice at heading stage. 3) Only 30% of the mercury content in rice was decreased by polishing and the rate was high at the first step. 4) No reduction of the mercury content was observed by cooking, but above 10% of the concentration was decreased in rice dusted with the fungicides at heading stage.