The digital radiation image evaluating method and apparatus record previously at least two radiation images with different exposed doses of the radiation, determine a value of evaluation of at least one of granularity and image quality of a digital radiation image for each of at least two digital radiation images obtained from at least two radiation images to obtain at least two values of evaluation, construct from at least two values of evaluation a correction curve for the value of evaluation to the exposed dose of the radiation and calculate by means of the correction curve the value of evaluation of the digital radiation image of a given dose exposed to the radiation. By the method and apparatus, the correct value of evaluation of the granularity and image quality of digital radiation image can be obtained for precisely predetermined doses exposed to radiation.