A radiation monitoring device realizes a high measurement function. Therefore, a radiation monitoring device includes: a radiation detection unit including a phosphor that emits light by incident radiation; a photodetector that converts a single photon or a photon group having a plurality of the single photons generated by the radiation detection unit into an electric pulse signal; and an analysis unit that analyzes the electric pulse signal. The phosphor emits light based on a plurality of light emission phenomena having different decay time constants. The analysis unit includes: a signal discrimination circuit that discriminates the electric pulse signal output from the photodetector; a dose rate calculation circuit that calculates a dose rate of the radiation based on a count rate of the discriminated electric pulse signal; and an application energy calculation circuit that calculates application energy of the radiation based on a peak value of the discriminated electric pulse signal.