Considering that the interior decorates the space, it can be said that there is a close relationship between light and space. Because of the color of light and the brightness, the natural light poured through the window is a big factor to change indoor atmosphere. Therefore, we focused on natural light in which how natural light varies in chronological order. In this research, natural light is dispersed by a prism and the spectroscopic lights are projected on a canvas by passing through an optical fiber. Thereby, we create an interior which utilizes both visible and invisible lights. “ Re-define” proposed in this research gives the chance to the audience to redefine the phenomenon of light which we can not recognize in ordinary life. Furthermore, “Re-define” have healing power because the fluctuation of natural light is used for the representation.