Sc doped CaTiO3, CaTi1-xScxO 3-δ (x=0.05, 0.1) was fabricated by a solid state reaction method and their conduction properties were investigated systematically using a 4-terminal method at various temperatures (500oC to 1000oC) and oxygen partial pressures. Oxygen partial pressure dependence of the conductivity was analyzed from a defect chemical point of view in order to estimate the ionic and the electronic partial conductivities. The ionic conductivity of CaTi 1-xScxO3-δ for x=0.05 and 0.1 were 0.018 S.cm-1 and 0.033 S.cm-1, respectively at 1000oC, and their ionic transference numbers were higher than 0.90 under SOFC operating condition. The both CaTi1-xScxO3-δ showed higher ionic conductivity than 8YSZ at measured temperature ranges. From these results, CaTi1-xScxO3-δ (x=0.05, 0.1) has high potential for alternative electrolyte materials of SOFCs, especially for ITSOFCs.