Abstract: An aluminum nitride sintered body characterized by comprising aluminum nitride as the main component, containing a titanium compound, and having a black color, a transmittance of 10% or less with the light having a wavelength in the range of from 500 to 650 nm and a heat conductivity of 120 W/m.multidot.K or more. The sintered body is produced by adding 0.05 to 5% by weight, in terms of Ti, of a titanium compound and a sintering aid compound and, if necessary, a compound capable of forming carbon after being thermally decomposed to an aluminum nitride powder, molding the mixture, heating the molding in vacuo, air or a nitrogen gas, a hydrogen gas or an atmosphere comprising a mixture of these gases until the residual carbon content is reduced to 2.0% by weight or less, and sintering the heat-treated mixture in a nonoxidizing atmosphere containing nitrogen at 1600.degree. C. or above. The titanium compound is Ti.sub.n O.sub.2n-1 or a solid solution comprising Ti.sub.n O.sub.