Titanium carbonitrides containing transition metal ((Ti, Me)(C, N), Me: transition metal) have been studied for applying them to cutting tools and wear- resistant tools. Thermal shock resistance is an important property of tool materials used in severer thermal environment. Therefore, the thermal conductivity of such materials is important to improve the thermal shock resistance of tool materials. The present work is aimed to clarify the effects of the composition of carbonitrides on thermal conductivity and electrical conductivity of carbonitrides. The experimental results showed that the thermal conductivity and electrical conductivity of carbonitrides decreased with increasing solid solution of transition metal.