PURPOSE: To construct a permanently usable membrane structure within a short time at low cost.

CONSTITUTION: A temporary membrane material 7 is placed on a setting plate 1, and the air is supplied between the temporary membrane material 7 and the setting plate 1 to expand the temporary membrane material 7 in dome form. A main membrane material 3 consisting of tetrafluoroethylene resin coating glass fiber cloth is arranged along the outer surface of the temporary membrane material 7. The seal membrane 9 of the temporary membrane material 7 is turned up, and the air in the temporary membrane material 7 is supplied to the space between the temporary membrane material 7 and the main membrane material 3 to expand the main membrane material 3, whereby a utilizing space is formed between the main membrane material 3 and the setting plate 1. Finally, the contracted temporary membrane material 7 is removed.