Temperature, humidity, and fungal concentration were investigated during the period from May 2019 to August 2021 to obtain information on the indoor air quality in the facilities of the National Archive of Koea, located at Seongnam, Daejeon, and Busan, respectively. The temperature and humidity of the undisinfected libraries was properly maintained for the preservation of papepr records. The airborne fungal concentration differed among the libraries, changed according to the season, and increased especially between June and August. Similarily, the concentration of airborne fungi in the hallways adjacent to the libraries also fluctuated depending on the season and showed a tendency to rise in the months when the ourside temperature rose. In general, the concentration of airborne fungi in the hallways was somewhat higher than that of the libraries. Importantly, it was identified that the concentration of airborne fungi exceeded the recommended standard (500 CFU/m3) by the Ministry of Environment of Korea only in the workroom where the classification and condition inspection of undisinfected records imported from outside were performed. Investigation of airborne fungal concentration from May 2021 to August 2021 showed that the 24 undisinfected libraries in Seongnam, Daejeon, and Busan were all good at 100 CFU/m3 or less. The results of this study are expected to be used as basic data to manage the indoor environment of facilities in the National Archives.