In this paper, we propose a flexible open 3D digital space combination scheme based on the concept of Symbiotic Computing which we have been promoting. Existing 3D collaborative work supporting systems have some limitations with their 3D digital space construction and inter-application cooperation because these systems have basically closed nature. To break these limitations, we are developing symbiotic collaborative work supporting system which can effectively support remote collaborative work. Our scheme enables us to easily and flexibly build collaborative work environment over the Internet by reusing and combining 3D structure definitions and applications designed by the general public such as WWW environment. In addition, we describe design and implementation of a prototype system, and confirm effectiveness of our proposed scheme through experiments by using the prototype system.