Disclosed is a non-thermofusible phenol resin powder having an average particle diameter of not more than 20 μm and a single particle ratio of not less than 0.7. This non-thermofusible phenol resin powder preferably has a chlorine content of not more than 500 ppm. This non-thermofusible phenol resin powder is useful as an organic filler for sealing materials for semiconductors and adhesives for semiconductors. The non-thermofusible phenol resin powder is also useful as a precursor of functional carbon materials such as a molecular sieve carbon and a carbon electrode material.