Dry dispersion of fine particles is discussed as a simultaneous process of dispersion and agglomeration. Various problems on the dry dispersion are summarized based mainly on our works and key terms such as partial dispersion efficiency and powder characteristic value are reviewed to analyze the dispersion mechanism and to evaluate easiness of dispersion for any kind of powder. Improvement of disperser unit is also suggested based on the analysis of dispersion process. Electrostatic charging, especially contact electrification between particle and its surface layer, seems to give further improvements on the dry dispersion of fine powder containing sub-micron particles. (C) 2009 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights reserved.