PURPOSE: To make a frame and the like hardly deformed by crossing tension members so as to constitute a space array.

CONSTITUTION: A roof device is formed by tension members. These tension members are crossed to define an isosceles triangle space array. Each tension member 7 is formed as a pair of cables. The tension members penetrate bearings 10, 11, 12 at intersections 8 thereof. These bearings are overlapped with each other secured by pins 13 at the intersections 8. The pins 13 are disposed orthogonally to a cable direction. Plates 14, 15 are attached on a top end part of the pin 13. Frames 7 are sandwiched between the plates 14, 15. These frames 17 hold a flexible transparent plastic sheet 6. The plastic sheet 6 covers a space defined by the cables. A rubber seal strip 17 is disposed between the adjacent frames 7.