Abstract: A method of neutralizing an accumulated charge on a surface of a specimen which is examined in a scanning electron microscope (SEM) or a scanning ion microprobe mass analyzer (IMA), utilizes an electrically conductive thin film deposited on a part of the specimen surface. The charge is due to irradiation by a primary charged particle beam from the SEM or IMA. The thin film is made conductivity with a specimen mount mounting the specimen, and the irradiating range of the primary beam covers at least a part of the thin film. Thus, the accumulated charge can be neutralized, thereby a resolution of the SEM being improved due to applying higher accelerating voltage for the primary beam, and measured data of higher reliability being obtained in the IMA.