For observation and analysis with SEM, EPMA, or SIMS, aerosol particles were collected on a flat substrate in an “aerosol impactor”. However, these particles, especially large particles, tended to form clusters at the center of the impaction point. Therefore, the analysis of an individual particle at the center became difficult. To overcome this problem, our previously developed small impactor was modified. In this modified impactor, a collection substrate was placed on an X―Y stage to scan the impaction point with in a 5 mm × 4 mm area during sampling, by using a DC motor, a cam, and a shaft. Any overlapping of the scanning lines for each scanning frame can be reduced by converting the ratio of the X and Y speeds into decimals. Upon comparing SEM images of particles collected using a conventional impactor and those using the above-mentioned impactor, it was confirmed that the evenness of the number of particles per unit area as well as the particle size distribution were enhanced.