Masaaki Naito* and Takasei Kusube**
* Kyoto University,
** Research fellow of Association for Promoting Science and Technology
+ Correspondence should be addressed to Masaaki Naito:
(Yoshida-honnmachi, Sakyo-ku, Kyoto 606-8501 Japan)

Abstract
Recently, Japan is quickly moving towards a circulation society. However, as long if the circulation systems undertaken at so many places so far are observed, it can be realized that there are various obstacles to be overcome, even concerning organic matters which are theoretically recyclable.
This report extracted the issues with which the present systems are concerned, and proposes strategies to overcome them. The most important fact extracted from the observations is that the difficulty lies mainly in the social system rather than in technological aspects. Based on these results, the authors are proposing several hints for reconstructing plausible systems both physically and economically.
A practical proposition made as the result of this work is that two different types of bio-recycling systems are possible in the future. One is the "Market based enterprise network type" and the other is a "Non-market based community type" . The significance of each type of systems is described for the future sustainable society.

Key words: bio-recycling, social system, market and non-market types, sustainable society