As for the frame of the Web advertisement, dealings are conducted in real time today. It is called RTB:Real Time Bidding. In RTB, dealings of ad spaces are conducted in the form of the auction, and unlike the auction of the former, goods (ad space) exist in large quantities. Such auctions are not in the former. Since RTB has just started, it is not well known about a motion of a market. So, Modeling of RTB market is performed in this re-search. It is the purpose to make a model to consider a motion of a RTB market. It compares with RTB and other various auction models. Finally we describe what was understood so far, future subjects and the view of research.