Akihabara Toilet. 100 Yen

Check this article.
http://ascii.jp/elem/000/000/355/355847/

High-end rest room is right next Akihabara station.
Called Oasis at akiba.

Only 100 Yen to use.  lol


map is here
http://www.city.chiyoda.tokyo.jp/service/00031/d0003130.html