A stabilized fluorine-containing polymer powder having an average particle size of 5 to 100 μm is prepared by contacting a fluorine-containing polymer powder, which is prepared by milling the fluorine-containing polymer and removing fine particles, fibrous particles and coarse particles by classification, with a fluorinating agent so that the total number of unstable terminal groups is decreased to 7 to 50 per 106 carbon atoms. This is a fluorine-containing polymer powder achieved a high coating efficiency in an electrostatic coating method and provides a film having good properties such as heat resistance, non-tackiness, low frictional property, chemical resistance, etc.