Abstract: An aluminum nitride granular powder is constituted by aluminum nitride sintered granules, the aluminum nitride granular powder having a maximum peak diameter of 30 ?m to 200 ?m in a volume-based particle diameter distribution obtained from maximum lengths of the aluminum nitride sintered granules measured with use of a dry particle image analyzer, with regard to the aluminum nitride sintered granules each of which has a particle diameter of not less than 30% of the maximum peak diameter, a ratio of the number of particles having an HS roundness value of 0.5 to 0.8 as measured with use of the dry particle image analyzer being not less than 15% relative to the aluminum nitride sintered granules each having the particle diameter.