Indium nanoparticles were obtained by vacuum evaporation technique of indium onto a glass carbon substrate in high purity Ar atmosphere. A technique is proposed for determining the nanoparticle dimensions and shape using a specially developed program. It is found that at a molten indium evaporation time from 10 to 30 s, indium nanoparticles with dimensions of 10–100 nm and crystallites with dimensions up to 500 nm are formed on the substrate. The largest number (up to 37%) of indium nanoparticles with dimensions of 50–100 nm is obtained at an evaporation time of 10 s; up to 52% of these particles have a shape different from spherical. The average diameter of indium particles increased from 140 to 190 nm with an increase in the evaporation time.