Microbial air monitoring in museums is usually conducted by applying airborn mold samplers and agars to detect the presence of viable mold that directly poses risks for mold growth on cultural properties.Recently,bioaerosol measuring devices that detect biofluorescence have been developed. These devices provide results immediately with easy operation than if airborn mold samplers are used because there is no need for cultivation. In the present study, bioaerosol measurement detecting biofluorescence and airborn mold measurement using a sampler were tested at various zones in a museum (ISO14644-1 Class 9) to ascertain how bioaerosol measurement can be applied for microbial air monitoring in museums. From the results of bioaerosol measurement using Microbe Sensor BM-300C (Sharp Manufacturing Systems) at the storage, unpacking space, and truck yard of Mie Prefectural Museum, it was found that bioaerosol measurement using this device is practicable inside museum facilities.However,for measuring outside air,which may be a major source of airborn mold that flows into the truck yard, it is necessary to modify the device for summer because bioaerosol concentration will exceed the permissible concentration that the device can measure. Other results obtained through simultaneous measurements of bioaerosol and airborn mold (BIOSAMP MBS-1000,PDA)at the previously mentioned zones showed that bioaerosol and viable airborn mold shifted almost parallel in each zone but that the ratio between bioaerosol and viable airborn mold was specific in each zone.Therefore, it is not possible to compare and evaluate viable mold concentration among zones in museums from the results of bioaerosol measurement alone. From the above, it may be said that bioaerosol measurement cannot be a direct substitute for airborn mold measurement for microbial air monitoring in museums although it can be applied for (1) fixed point monitoring in museum storages to detectabnormal bioaerosol concentration changes, which are equal to contamination events, (2) monitoring dusts fluttered by visitors in exhibition rooms to evaluate floor cleaning accomplishment and its frequency, and (3) evaluating underlying risks of accumulatedbioaerosol on cultural properties becoming nutrients (carbon source) for viable mold.