The melting temperatures of UO₂, UO₂-6wt%Gd₂O₃, UO₂-12wt%Gd₂O₃, UO₂-2wt%Er₂O₃, and UO₂-4wt%Er₂O₃ fuels were measured. Fuel materials were loaded in a tungsten capsule of which shape met the black body condition. The melting temperature was measured by the thermal arrest method during heating of the capsule in an induction furnace. The measured melting temperature of UO₂ fuel was 2815±20℃. The solidus and liquidus temperatures of UO₂-Gd₂O₃ and UO₂-Er₂O₃ had also been measured, and it was observed that the solidus temperatures of them were lower than the liquidus temperature by 15 ~ 25℃, Measured melting temperatures of UO₂, UO₂-Gd₂O₃ and UO₂-Er₂O₃ fuels were as follows: ◁표삽입▷