The electrical conductivity of REF3-LiF (RE = La and Nd) molten salts (xREF3 = 5 mol％-40 mol％) was systematically measured over the temperature range from 1223 to 1423 K by using continuously varying cell constant (CVCC) method. Electrical conductivity values of LaF3-LiF and NdF3-LiF molten salts within the studied ranges are 4.11-9.39 and 3.62-9.51 S/cm, respectively. The composition and temperature dependences of electrical conductivity and the factor of RE2O3 on electrical conductivity were investi-gated. The electrical conductivity nonlinearly decreases with the increasing mole percent of REF3 for the changing of structural ion in molten salts. A good linear relationship between the natural logarithm of electrical conductivity (lnk) and the reciprocal of the absolute temperature (T-1) can be interpreted by the trend that electrical conductivity linearly increases with increasing temperature. Although it is an important factor of RE2O3 on electrical conductivity, the influence of RE2O3 on conductivity is small for the very limited solubility of RE2O3 in REF3-LiF molten salts. The results of this work supplement the present electrical conductivity data of rare earth fluoride electrolyte.