Question 1

Where is Kosei Hospital?

Accepted Answer

Kosei Hospital is in Suginami, Tokyo, Japan. You can see its exact position from the map coordinates and the Street View link.

Question 2

Which scene of Negative Positive Angler does Kosei Hospital appear in?

Accepted Answer

Kosei Hospital appears in EP10 of Negative Positive Angler.

Question 3

Can I visit Kosei Hospital?

Accepted Answer

Yes. Kosei Hospital is a real place you can visit. Check what it looks like on Street View before you go.

Question 4

Where was Negative Positive Angler filmed?

Accepted Answer

Anime and manga are not filmed the way live action is. Their backgrounds are painted from photographs of real locations, and Kosei Hospital is one of those real places (EP10).