This invention relates to an interior panel unit having a structure in which a plurality of rectangular floor base members to be installed on a foundation floor of a room are connected to each other by base joint members. A plurality of fundamental support members having the same height and a plurality of connecting support members having the same height as that of the fundamental support members are located on each floor base member. Each floor panel member supported by the fundamental support members and the connecting support members is arranged to assure a predetermined space with the corresponding floor base member. Cables and various types of equipment which constitute an office-automation system are mounted in the space defined by the floor panel member and the floor base member. The space defined by the floor panel member and the floor base member is partitioned by vertical and horizontal separator members. The cables and various types of equipment are appropriately arranged in the partitioned space.