B'z The Best "Ultra Treasure" is a compilation album by the Japanese hard rock duo B'z.

It was released on September 17, 2008, and it is part of their 20th anniversary celebration.

The album track listing was decided by fans who voted on a poll at the B'z 20th anniversary website.

The fans could vote for all but three songs that have ever been released by B'z.

All tracks by B'z ^ Shipments figures based on certification alone.