An aluminum nitride powder containing a very small amount of coarse particles. An aluminum nitride powder which provides a resin composition having high affinity for resins and high moisture resistance.
The aluminum nitride powder has a volume average particle diameter D50 of 0.5 to 7.0 μm in particle size distribution measured with a laser diffraction scattering particle size distribution meter, a D90/D50 ratio of 1.3 to 3.5 and a BET specific surface area of 0.4 to 6.0 m2/g and classified by removing coarse particles whose particle diameter is more than 5 times as large as D90. When resin paste obtained from this aluminum nitride powder and a resin is measured with a grind gauge, the upper limit particle diameter at which a streak is produced is not more than 5 times as large as D90. Since the classified aluminum nitride powder is surface modified, the aluminum nitride powder which has high filling property in a resin and is excellent in the moisture resistance and insulating property of a resin composition is obtained.