In a forest ecosystem, wood decaying fungi are major organisms exploiting the fallen logs, and show a great species diversity even within a forest. It is known that both species richness and species composition of wood decaying fungi are affected by the log properties such as volume and decay stage. In my field study, I found that wood decaying fungal species could be classified into several guilds depending on volume and decay stage of the logs, suggesting their non-random habitat preference. Insects may play a role in the habitat selection of the wood decaying fungi by directly dispersing fungal spores or by changing the chemical and physical properties of the logs. Although several examples are known for specific fungus-insect interactions, it is still unclear whether such interaction influences wood decaying fungal community. To investigate on this hypothesis, I set up a field experiment in Tomakomai experimental forest, and examined the effect of insects on wood decaying fungal community on fallen logs of Acer mono and Quercus crispula. I excluded insects by putting the logs in tetrahedron exclosures, and as a control treatment, I placed the other logs in the exclosures with small windows which made the logs inside accessible to insects. I want to show the result of this experiment, and discuss the potential effect of insects on wood decaying fungal community.