The purpose of the research is to reveal the process of the formation of modern church architecture in 20th century. In order to do that, neo-gothic architecture which starts in the point of view of ethic in the 19th century will be discussed first. Then the relations between Arts and Crafts Movement and church architecture which is the beginning of modern architecture movement will be revealed. After that, the purpose of Secession's church architecture which tried to separate from old architecture and the formation of background of localistic church architecture which is one of the modern church architecture will be discussed. Based on those discussions, the research in concluded the several characteristics of church architecture which makes it modern architecture. The research is focused to the portions which is related to the church architectures among the architectural conditions so complicated as to be easily confused. And also it is focused the architect those who should be mentioned in the same context and their works.