Interior design has diverse functions and roles according to recent changes in life and cultural style. As the meaning of space varies, the furniture as another element of the space should also be planned and included in the beginning of the project to accomplish its functional role on the finished space and not only be placed. The relationship between Interior space and furniture should be studied and understood at the same realm because they have a complementary relationship. The final destination of design, which is very challenging to accommodate people, the designer needs to approach to the interior space and furniture in a cognitive view. The study of Semiotics views in a knowledgeable and epistemological way every element as a sign and by the relationship of their characters it makes to understand the structure of the signs. Charles Sanders Peirce, a leader of Semiotics in USA, classified the structure of Sign into Representamen, Object and Interpretant to complete the theory which could systematically describe physical characteristic and function of the Sign and its significance in practical use. Peirce stated that all nine types of Sign would be generated if each structure of Sign in combined with three categories of Sign such as Firstness, Secondness, and Thirdness. In this study, based on Peirce's nine types of Sign, the interrelationship between space and furniture in interior design was investigated with examples in Living Space, Office Space, and Commercial Space, respectively. In the category of Representamen, which can be classified into Qualisign, Sinsign, and Legisign, it is a feature of Living Space to be expressed in harmonized and stabilized ways. In Office Space vertical/horizontal elements and open expression are differently showed depending on fields. And splendid and interesting expressions are showed in Commercial Space. In the category of Object, which can be classified into Icon, Index, and Symbol, each function of Sign has distinctly been showed as Symbol in Living Space, Index in Office Space, and Icon in Commercial Space, respectively. In the category of Interpretant, which can be classified into Rheme, Dicisign, and Argument, it was found that space image of Living Space is transferred to human being, Office Space regulates human bing, and Commercial Space binds human being with the space. In conclusion the function of the interior space and the furniture could be explained in another way with re-interpretation of interrelationship among interior space elements in the concept of Semiotics. It is expected that interpretation with Semiotics in interior design will grow to new theory of design.