Guarantor
Is there an organization in Japan that serves as a guarantor for foreigners in Japan who want to rent apartments?
Yes, there is such an organization. It is called the Japan Guarantors Association and you can reach them at (03) 5333-3816.
You can also reach them online at www.igs55.com. At the same time any "gyosei shoshi" or administrative lawyer can perform the same service. The usual fee is one month's rent for serving as your guarantor.