Polia nebulosa and Hyboma adaucta (Lepidoptera: Noctuidae) were collected from nest boxes of the Siberian flying squirrel Pteromys volans orii (Mammalia: Rodentia: Sciuridae) in Obihiro, Hokkaido, Japan. This is the first record of moths collected from nests of flying squirrels (tribe Pteromyini). These two species probably used the nests of P. volans orii as overwintering sites since all the moths found were in an overwintering state when collected, both moth species do not feed on detritus, and the temperature in the nests is assumed to be higher than that of the outside.