The measurements on specific heats of liquid In-Te and Se-Te alloys have been carried out to explore the mechanism of metal-nonmetal transition in the liquid state. A large temperature dependence of the specific heats has been observed around In 2 Te 3 for In-Te alloys and in the Te rich region for Se-Te alloys, respectively. These large specific heats are fully explained in terms of Schottky-type specific heats due to the transition from non-metallic state to metallic one in addition to Dulong-Petit's values. The specific heat of liquid Se-Te system in the Se-rich region is, on the otherhand, not so much dependent on temperature and is almost equal to 8 cal/g-atom·deg. From these, it is inferred that in liquid Se-Te alloys there exists an endothermic reaction due to the recombination of bonding in the Te-rich region, while there exists neutral broken bonds in the Se-rich region.