PURPOSE: To improve the opening factor of a roof by providing a rotary shift type roof at the lower section, and providing a horizontal shift type roof having a double-film structure and jointly using the air via through holes passing the air at the upper section.

CONSTITUTION: A fixed roof 10 mounted on an outer wall 9 and a rotary shift type roof 6 stretched with a film material 12 on the surface of a main skeleton 11 and moved in the outside direction of the roof 10 via a rail 13 provided on the outer wall 9 and a rail 17 provided on the outer periphery of inner circular beams 15 are formed at the lower section of a dome roof 1. A horizontal shift type roof 5 is formed in a bag shape, bags are connected in a semi- spherical shape, through ports 18 are provided, a double-film 4 jointly using the air, circular beams 9, bed legs 3 and dollies 7 are provided, and it can be moved on rails 2. If the plot area has a margin, the lower section is made the rotary shift type and the upper section is made the horizontal shift type, thereby a sufficient opening factor can be obtained.