Abstract Asian dust (Kosa) events transport airborne microorganisms, which significantly impact biological ecosystems, human life, and ice-cloud formation in downwind areas. However, composition and abundance dynamics of airborne bacteria have rarely been investigated in downwind area during Kosa events. In this study, air samplings were sequentially performed on the top of building (10-meter altitude) within the Kosa arrival area (Kanazawa City, Japan) from May 1 to May 7, 2013, when a dust event occurred. The particle concentrations of bacterial cells and mineral particles increased ten times during Asian dust event comparing non-dust event days. A 16S rDNA clone library prepared from the air samples mainly belonged to the three phyla, such as Firmicutes, Cyanobacteria, and Alpha-proteobacteria. Cyanobacteria mainly including a marine type of Synechococcus species dominated at the first phase of dust event and were continuously detected during dust event. The clones belonging to Alpha-proteobacteria were mainly detected at the initial and last periods of dust events and clustered with marine bacterial clade (SAR clade) and Shingomonas spp. In the midst of dust event, sequences of Bacillus subtilis and B. pumilus in Firmicutes predominately appeared, and they are known to dominantly inhabit atmospheric area in KOSA source area (Chinese desert). The clones obtained after the dust event finished were mainly related to B. megaterium, which are thought to originate from local terrestrial areas. Our results suggest that airborne bacterial communities on the surface ground changed their species compositions during dust event, and are composed of terrestrial and pelagic bacteria which, are transported from East Sea and China continental area by Kosa event.