To exclude a noise caused by a radio wave and vibration or the like from a detection signal, in a radiation measuring device (especially, a personal dosimeter).

In the noise elimination method, a noise is reduced by utilizing that a noise signal is generated at both the polar sides of a baseline while a radiation signal is generates on one polar side of the baseline. A comparator 22 extracts a signal component at one polar side in a detection signal, namely it outputs a signal 100 including both of the radiation signal and noise. A comparator 24 extracts merely the signal constituent at the other polar side in the detection signal. More specifically, a signal 102 including merely the noise is outputted. A counter operation part 26 subtracts the signal 102 from the signal 100, thus reducing the noise.