The behavior of a negative pole of a carbon plate (a mixture of graphite with glassy carbon) in a eutectic LiCl-KCl binary molten salt has been investigated at 360-500 degrees C, as a fundamental study on high temperature lithium secondary cells. Both cyclic voltammetric and galvanostatic charge/discharge data suggested that reversible insertion/extraction of lithium can take place accompanied by stage formation. The interlamellar distance of carbon increased upon lithium insertion and the coulombic efficiency became higher with galvanostatic cycle number.