In this study, the concentration and size distribution of fine dust particles were analyzed by measuring the dust in air generated during the cleaning of an indoor office. We measured the PM10, PM2.5, and PM1.0 and analyzed the size distributions of particles larger than 0.3 µm in diameter during cleaning. The results showed that the concentration of PM10 increased rapidly during cleaning, whereas the PM1.0 did not increase. Prior to sweeping the floor with a broom, the fine dust concentration was ~50 µg m–3, but it increased to ~400 µg m–3 as the sweeping progressed. When a vacuum cleaner was used, the concentration of PM10 increased, but the increase in PM2.5 was relatively small. As in the case of sweeping, the PM1.0 did not increase while vacuuming.