This paper has two main purposes : first, it aims to explain the interesting historical phenomenon of the prosperity of christian lay organizations in early modern Japan. Second, from the sketch describing the process of the introduction of the christian confraternity movement into Japan and its development, I argue for the effectiveness of the hypothesis of "connected histories". The historical questions to be answered are 'why there was such activeness of religious communities around Japan in the later 16th century?' and 'in spite of lack of priests, how were the communities able to form and be run?' The key term which sheds light on this study is confraternitas. An overview of the origin and development of the European confraternities shows there existed in people's mind a vague sense of angst and the obsessive apocalyptic concept in the later medieval period. In such chaotic world, confraternities found their place mainly through the form of charity and faith-oriented movement. This new and independent type of community took its root among common people, and gave much influence upon the strategy of the Church. In Japan, Jesuit missionaries enjoyed success around several local regions. Instead of parish system, they chose to found kirishitan communities, which is surely the adaptation of the european confraternitas. After the expulsion of the missionaries in 1587, the communities took a new phase of transformation with strong concern with an inward character, such as the mutual help and the coordination of individual spirituality. Behind the apparent success, there lies Japan's religious community, which is the dōjō system created by the Jōdo Shinshū Buddhist sect. This tradition was founded by Shinran and had resemblances in maintaining its organizations with the European confraternitas. Most of all, along with the global change of climate, the dōjō system had also intuitive anxiety of people as its spiritual background. All of these considerations explain how the Japanese kirishitan appeared as a substitution for the continuous chanting of prayers to the Buddha. I think that this case shows clearly an aspect of 'connected history' in Europe and in Japan, and also believe that the possibility of that connection can be explained through the 'mind' that is common in both the Europeans and the Japanese.