PURPOSE: To provide an expandable antenna reflector for the space which is securely developed on an orbit without entanglement in a cable network holding a refrector.

CONSTITUTION: An expandable structure developing a metallic mesh 1 constituting a radio reflecting surface, the cable network 2 holding the shape and a film surface 5 for preventing entanglement, which is put up in the cable network 2, on the orbit and holding the metallic mesh 1 and the cable network 2 is provided. Thus, entanglement can be prevented by the film surface 5 which is put up in the cable network 2 and effect that secure development can be executed eve if the reflector is enlarged.