The blur phenomenon, in which the boundaries of fields or roles become vague, has become an important concept of design in the 21st century. In furniture design, the physical boundary between furniture and space and that between space and furniture has been broken down and their meaning tends to be redundant. This concept was begun by a variety of furniture designers who led the trends about 30 years ago. A progressive exhibition titled ${ulcorner}$Living Tomorrow${lrcorner}$, which was included in the Koln International Mobelmess from 1968 to 1970, showed that the blur phenomenon in furniture design has never actually been novel. These exhibitions and the works exhibited in the events are still recognized as progressive examples that proposed an avant-garde concept of life. They are in line with the current furniture design based on spatial concepts, which has been created by the blur phenomenon. The purposes of this study are to determine the cases of furniture design that enable the so-called spatial functions beyond the simple functions of seating, use, and display, from those of furniture design and to research their characteristics. In this study, furniture based on spatial concepts means furniture that creates 3D spaces consisting of the floor, walls, and ceiling by the blur phenomenon that occurs from the spaces among these pieces of furniture. The organization of this study is as follows; In Chapter 2, a background on the generation of furniture design based on spatial concepts is described based on the research literature of this socio-cultural phenomena. In Chapter 3, the cases of relevant furniture design redescribed. In Chapter 4, the collected cases are analyzed and their characteristics described. In Chapter 5, Chapter 1 to Chapter 4 are summarized and conclusions are given. In addition, future research is proposed.