This study examined the characteristics of furniture design in the early Modernism that occurred in the early 20th Century through the relationship with modern arts. The furniture design of the early Modernism was established in the early 20th Century based on the simplicity and honesty of the Art and Crafts Movement and Anti-Historicism in Art Nouveau. During this period, the necessity of mass production became critical due to the radical industrialization and new social demands. In such periodic stream, the furniture design of the early modernism pursued simplicity and geometric beauty based on functionalism. The efforts to discover the fundamental structure of furniture were intensified. It was not limited to furniture design but was also exercised in the huge periodic transformation that progressed in every field of art including architecture. The Modernism art has also been connected to Cubism and spread into an abstract direction. While questioning the potential essence and progressing the study on genuine characteristics, the Modernism art tried to return things into their substantial looks and reorganize them conceptually, rather than reproducing external objects. The furniture that was secondary to a part of architecture and interior accessory transcended its decorative purpose. It pursued the structure to follow its fundamental purpose as furniture. Such tendency corresponded to the direction that Post-Modernism followed. Likewise, both art and design had the revivable and abstract characteristics based on the identical objective in ideology. For this reason, the formative and geometric characteristics of the early modernism furniture design have a mutual relationship with modern arts. Particularly, such tendency intensified and progressed through the Bauhaus in Germany. Based on such facts, this study proved that the early Modernism furniture design in the 20th Century tended to appear in common arts including the art and design according to the social demand of the huge periodic stream. Furthermore, the ideology that was adopted in art and design, as well as its formative characteristics, was examined through the mutual relationship of modern arts and design.