Black fungus gnats play an important role as the decomposers in the forest ecosystem. Their larvae live on various organic matters, and the subfamily Sciarinae, in particular, have restricted habitats that feed on dead woods in the deep forest. We compared the biodiversity of family Sciaridae from two different habitats, the clear-cutting area (CA) and the pitch pine forest (PF) by the emergence traps (ET) and the pitfall traps (PT) from May to October, 2010. A total of 12 species were reliably identified to the species among 19 unique taxa belonging to 9 genera 4 subfamilies from 716 collected black fungus gnats. Taxonomic studies show that Corynoptera bicuspidata (Lengersdorf, 1926) (200 individuals, 27.9 % of total) and Cory. sinedens Hippa, Vilkamaa & Heller, 2010 (74 individuals, 10.3 % of total) dominate in the PF and the CA, respectively. Species richness and abundance of CA is lower than those of PF. Any species of subfamily Sciarinae were not collected in the CA. These findings indicate that the biodiversity of Sciaridae was influenced by forest management such as clear cutting, which leads to the changes of canopy cover, dead woods and leaf litter layer.