Boron neutron capture therapy (BNCT) is a type of radiation therapy which can selectively kill tumor cells. The irradiation field employed in BNCT is a high intensity with a wide energy range, and undesired neutrons can be irradiated in a patient's body during the treatment as a result. These neutrons are categorized into thermal, epithermal, and fast neutrons on the basis of their energy ranges. Their individual doses inside the body should be measured in real-time because their relative biological effectiveness differs in each neutron energy region. Therefore, in this study, we developed a system comprising real-time neutron detectors with separate sensitivities for each neutron type with an Eu:LiCaAlF6 scintillator combined with a polyethylene moderator. We tested the performance of the detectors and performed dose evaluation using a water phantom representing the human body and compared the results with those obtained via a commonly used activation method. Thermal, epithermal, and fast neutron doses were successfully measured in real-time at the surface of the entire body, and we were able to estimate the fast neutron dose inside the body.