The monodisperse Ag particles of various sizes from 20 nm to 110 nm are charged by the condensation and evaporation method and its charge distributions are measured by the SMPS. Those particles becomes ethylene glycol droplets of same size by condensation and charges with high charged droplets evaporates through evaporator. The charge distributions of that are uniform, regardless of the particle size. But when the particle is smaller than 20nm, some of the charges evaporate from the surface of them due to the ion evaporation. Moreover since the electrical mobilities of the highly charged particles smaller than 20nm are larger than the maximum not measured perfectly.