In Akihabara, where various specialty stores accumulate, people gather searching for limited and rare products and exchange them to share their hobbies and interests outside the store, forming a kind of public sphere.

 This paper clarifies the mechanism of forming "the place for exchanges of goods".

 To grasp this mechanism that are common in the outdoor space of Akihabara is also important in considering the value of downtown, which used to be discussed with words "bustle" and was not considered its social meaning.

 1) Geographical characteristics of group staying behavior on the street

 By patrolling Akihabara district, the distribution of places for exchanges of goods on the street was clarified from the wide-area viewpoint. Through this survey 12 locations were extracted where "appreciation and exchange" activities were concentrated, and from these locations it became clear that place for exchanges of goods tend to be formed in the near ground where manga, anime, and game content is sold.

 2) Behavior and spatial transformation of places for exchanges of goods

 From the fixed-point observation investigation, the change of the range in which space for exchanges of goods forms and the change of the behavior were analyzed. As a result, special characters of places where exchanges of goods are likely to happen were grasped from a microscopic viewpoint. It has become clear that place for exchanges of goods occurs avoiding the flow of people. It was also confirmed that the larger the number of members, the more they stayed in the environment surrounded by street objects.

 3) Behavioral psychology of people who form places for exchanges of goods

 Hearing investigation clarified what kind of behavioral psychology were seen behind forming the places for exchanges of goods, and what kind of actions were done for making their own place on the street. As a result, two types of actions were identified: "exchange of goods" and "exchange of information". It was confirmed that places for exchanges of goods occurs not only in search of a consensus of interests, but also in search of mutual empathy through the exchange of information in which people can deepen their knowledge of hobbies and preferences. It also became clear that they formed or joined in places for exchanges of goods with 9 kinds of behavioral psychology.