Most parts of Japan are covered with forests that play multifunctional role in environmental conservation. Forest connectivity in the Japanese islands was evaluated by calculating a newly proposed index “CON” defined as the number of the neighboring forest grid cells in 3×3 grid cells, using a standard grid (approx. 1km grid cell) database of vegetation developed by the Japan Environment Agency. The results of our study indicated that the forests in Chugoku district are comparatively fragmented for its forest coverage ratio, and forest connectivity is strongly correlated to topographical factors.