In our society, there are many opportunities to exchange opinions on decision. Problems may occur when we exchange opinions. It is desirable for solving problems to make an environment that can achieve a smooth opinion exchange. There are "divergence phase" and "convergence phase" in the opinion exchange for decision. The divergence phase is to enumerate various choices related to the subject, and to consider possibility. On the other hand, in the convergence phase, participants investigate alternatives arose in the divergence phase, and argue for making a single conclusion.
In this paper, we focus on the convergence phase, and propose a system that supports the process narrowing the listed alternatives by using RFID tags. That is, the system supports the smooth progress of opinion exchanges by controlling the time, the speech order, and the alternative evaluation for leading a single conclusion that many participants can accept.