There is disclosed an aluminum sintered body prepared by sintering aluminum nitride and additives, which consists essentially of(a) aluminum nitride,(b) at least one compound selected from the group consisting of an aluminum compound of a rare earth metal, an aluminum compound of an alkaline earth metal, and an aluminum compound of a rare earth metal and an alkaline earth metal, and(c) at least one element selected from the transition elements consisting of Groups IVa, Va, VIa, VIIa and VIII of the periodic table, and/or at least one compound comprising the element, and the rare earth element, alkaline earth element and transition element are supplied by the additives.