This study is based on an investigation into the relationship between space, structure and form in architecture. It is divided basically into three stages. In the first stage, I attempt to review and to clarify general architectural and structural ideas from the point of view of the composition of three basically different functions each of which would require, by itself, a structure of bridging long span. This stage of my research includes "problem No. 1" and "problem No. 2". In the second stage, architectural and structural problems are discussed which spring from the specific functions of a Natatorium, an Auditorium or a Gymnasium of the given scale. This stage includes "problem No. 3" of my research. The third, or last stage, includes a survey of various long-span possibilities, and the selection and development of a prototypical example that most directly, simply, and clearly houses the various functions. This resulting long-span cable network structure serves as a demonstration of the relationship between space, structure, and form.