The macaques at Takao San?

Would actively recommend that you avoid that enclosure.

My thoughts from a previous thread:

"Tip: Don't visit the monkey park (despite repeated visits over years I'd never gone inside, then my father-in-law took us in one time as we had his young grandchild with us). Even more sad and depressing than I imagined it would be - nothing like Jigokudani near Nagano"

Unless you're actually thinking of Jigokudani. Which is near Nagano. Not "just outside Tokyo" - as Google Maps can show you.