Forest-floor vegetation and regeneration of tree species were investigated inside and outside a deer-proof fence that had been constructed 7 years earlier in a cool temperate deciduous forest in the Tanzawa Mountains, where dwarf bamboo (Sasamorpha borealis) had been browsed and diminished by sika deer. This study examined the effect of the deer-proof fence on tree species regeneration. The vegetation cover on the forest floor, cover and culm height of dwarf bamboo, and density and height of seedlings and saplings were higher inside the fence than outside the fence. Species composition consisted of dwarf bamboo, trees, and shrubs inside the fence, whereas annual herbs and short perennial herbs were found outside the fence. The density of regenerated trees was higher inside the fence than outside the fence, and the difference was more than 6-fold. The heights of almost all tree species inside the fence ranged between 40 and 60 cm, and though some tree heights for 9 tree species were higher than that of dwarf bamboo inside the fence, many trees outside the fence had heights of only about 10 cm. Based on these findings, it was concluded that the deer-proof fence facilitated the establishment and growth of tree species as well as the recovery of dwarf bamboo, and that the fence was an effective means of restoring cool temperate deciduous forest. Further monitoring is required to predict the future development of regenerating trees and to determine an optimal vegetation management plan.