A radiation measurement device comprising a calculation unit in which respective wave height values of voltage pulses from a radiation detector are made to correspond to radiation energy values and a count that is the number of the voltage pulses is separately generated for each of a plurality of channels corresponding to the wave height values so that a wave height spectrum is generated and a dose of a radiation that has entered the radiation detector is calculated based on the wave height spectrum, wherein the calculation unit comprises: - a spectrum generation unit that is configured to generate the wave height spectrum; - a dose rate calculation unit that is configured to calculate a dose in the radiation energy value corresponding to each of the channels, based on a count generated in each channel by the spectrum generation unit , to integrate the calculated dose for the whole measurement range for the radiation energy value so as to obtain an integral dose, and to divide the integral dose by a measurement time so as to obtain a dose rate; characterized in that it further comprises - a correcting dose rate calculation unit that is configured to calculate a neglected dose rate which is a dose rate distributed at an energy the same as or smaller than a measurement limit of the measurement range of the radiation energy values and which is not reflected in the dose rate calculated by the dose rate calculation unit, based on a count in at least one channel that includes a lower limit within the measurement range, out of counts generated in the respective channels by the spectrum generation unit , and based on the energy resolution of the radiation detector , and to obtain a correcting dose rate, that is a radiation dose per unit time, from the calculated dose rate; and - a dose rate correction calculation unit that is configured to multiply the correcting dose rate obtained by the correcting dose rate calculation unit by a correction coefficient, obtained based on the energy resolution of the radiation detector , and to calculate a dose rate of a radiation that has entered the radiation detector by adding the multiplied correcting dose rate to the dose rate obtained by the dose rate calculation unit . - a spectrum generation unit that is configured to generate the wave height spectrum; - a dose rate calculation unit that is configured to calculate a dose in the radiation energy value corresponding to each of the channels, based on a count generated in each channel by the spectrum generation unit , to integrate the calculated dose for the whole measurement range for the radiation energy value so as to obtain an integral dose, and to divide the integral dose by a measurement time so as to obtain a dose rate; characterized in that it further comprises - a correcting dose rate calculation unit that is configured to calculate a neglected dose rate which is a dose rate distributed at an energy the same as or smaller than a measurement limit of the measurement range of the radiation energy values and which is not reflected in the dose rate calculated by the dose rate calculation unit, based on a count in at least one channel that includes a lower limit within the measurement range, out of counts generated in the respective channels by the spectrum generation unit , and based on the energy resolution of the radiation detector , and to obtain a correcting dose rate, that is a radiation dose per unit time, from the calculated dose rate; and - a dose rate correction calculation unit that is configured to multiply the correcting dose rate obtained by the correcting dose rate calculation unit by a correction coefficient, obtained based on the energy resolution of the radiation detector , and to calculate a dose rate of a radiation that has entered the radiation detector by adding the multiplied correcting dose rate to the dose rate obtained by the dose rate calculation unit . <EOS>