The Heavy Water Thermal Neutron Facility of the Kyoto University Research Reactor (KUR) was wholly updated in March 1996 mainly for neutron capture therapy. The performance as a neutron irradiation facility was improved using the epithermal neutron moderator of the aluminum-heavy water mixture (Al/D2O = 80/20 vol%), the neutron energy spectrum shifter of heavy water, and the thermal neutron filters of cadmium and boral plates. The clinical irradiation utilization under the full-power (5-MW) continuous KUR operation was realized employing both the radiation shielding system, consisting of the shielding door and irradiation room, and the remote carrying system for a patient. The safety and utility of the facility were improved due to the safety observation system.