The electrical conductivity of highly pure polycrystalline $Yb_2O_3$ has been measured from 650 to 105$0^{circ}C$ under oxygen pressure range of $10^{-5}$ to 102 torr. The conductivity dependence of oxygen pressure in the temperature region from 750 to 105$0^{circ}C$ is approximated by $sigma$ $alpha$ $Po_2^{1/5.3}$. This shows that the conduction mechanism is associated with doubly ionized metal vacancies. Fairly low activation energy and the lack of oxygen pressure dependence are found over the temperature range of 650 to 75$0^{circ}C$. The conduction mechanism can be explaned by not metal vacancies, but hopping oxygen ions in the oxide.