A chord truss roof includes a ring-girder, cross beams arranged radially around the ring-girder, chord members stretched between the respective cross beams and the ring-girder. The roof supports itself by tensioning the chord members. The ring-girder has an upper compression ring, a lower tension ring, and plural struts connecting the two rings. The chord members arranged opposite one another with both end portions of the tension ring interposed therebetween are connected to the corresponding end portions of the tension ring, and are joined to one another via connection members which are disposed between both end portions of the tension ring. Further, each strut is provided along a line which bisects the angle made by a corresponding chord member and the plane defined by the tension ring.