This study was carried out to investigate how airborne bacteria are distributed under different temperature conditions while cultivating oyster mushrooms by setting the indoor temperature of the cultivation room to 10°C, 15°C, 20°C, 25°C, and 30°C. The surveys were conducted in April and May, respectively. Airborne bacterial concentrations were distributed in the range of 1.61 × 102 ~ 3.67 × 102 CFU/m3 in April and 5.47 × 102 ~ 7 × 103 CFU/ m3 in May. In May, the indoor air quality maintenance standard (8.0 × 102 CFU/m3) was exceeded in the 10°C, 20°C, and 25°C cultivation rooms. Bacterial concentrations increased significantly in May compared to April. Bacterial concentrations were different between the cultivation rooms at different temperatures. The difference was more pronounced in May than in April. A total of 15 genera and 20 species were isolated from the indoor air of the oyster mushroom cultivation rooms. Overall, it was most abundant in Actinomycetia. Among the species identified, Agrobacterium radiobacter, Brevundimonas vesicularis, Kocuria palustris, K. salsicia, Lysinibacillus fusiformis, and Sphingobacterium siyangense are known to affect human health. This is the first report of airborne bacteria in cultivation rooms at different temperatures used for oyster mushroom cultivation. The results of this study are expected to be used as basic data to understand the indoor environment of thermophilic mushroom cultivation facilities.