Potentiometric cell oxygen sensors using $CaF_{2}$ were fabricated for monitering the oxygen partial pressure in the low temperature range ($300^{circ}C{sim}$500^{circ}C). The disk type oxygen sensors consist of a reference electrode: Air($O_{2}:21%$)|Pt, a solid electrolyte $CaF_{2}$, and a sensing metel Pt electrode. And the change in open circuit emf of the disk type cell was about 45mV for the oxygen concentration range, $0.1%{sim}10%$, at the cell temperature of $400^{circ}C$. Also, the reference electrode incorporated type sensor showed the change of 40mV for 0.1% to 10% oxygen partial pressure range.