First of all corner is an essential element to consist the space, but there is not much solid study and basic concept on the corner. The most important reason is the lack of the concept on the corner. The definition of corner by itself carries the term of space. Accordingly arguing the corner in space is to characterize the space. The corner is an important element to build up the space. The purpose of this study is to give a definition on the comer in space and suggest the way of practical use. The corner in space began to transform after Cubism. Therefore this study is bounded after Cubism era. The focus of study on plastical expression properties is on the view point by each era and constitutional point of view. In conclusion, the concept of corner has been switched from the concept of structure to concept of decoration. Also, study found that the concept of corner has the ideology, medium, and characteristics of boundary.