I found this↓
"Tokyo Vegans club"
菜食レストラン情報[Vegan Restaurant Guide]―東京ヴィーガンズ・クラブ [Tokyo Vegans Club]
Some restaurants can serve vegan food, but most of them are mainly for vegetarian.
As RealJamessan says, we Japanese are not familiar with vegan. I had never known about vegan until I went to America f^^;