[en] For the purpose of evaluating absorbed dose in the material irradiated with a high-power X-ray generator the effective energies of X-rays were obtained by various methods such as the HVL measurement, the ionization measurement based on cavity theory, and X-ray spectrometry. Through a comparison between the results of experimental values, the effective energy matching with practical irradiating condition was evaluated. It was 95 keV for tube voltage of 150 kV. Based on this value, the dose characteristics were obtained with ionization chambers, Fricke dosimeter, polymethylmethacrylate dosimeter and cellulose triacetate dosimeter, and a general formula for evaluating the absorbed dose was proposed with a consideration of the composition, the size, and the thickness of the irradiated material. (author)