PURPOSE: To dry and store grain while keeping high in quality and to reduce running cost and construction cost of a processing facilities of the grains.

CONSTITUTION: An air chamber 133 is formed by a double structured roof 13 of an outer tent 131 and an inner tent 132, a side wall tent 16 is formed by extending the outer tent 131 by way of providing a specified space part between external walls 14, and a lower end of this side wall tent 16 is opened. Consequently, by communicating the space part 15 and the air chamber 133 to the outside air through the opened lower end of the side wall tent 16, it is possible to carry out natural convection of the air in the air chamber 133 and the air in the space part 15, to thermally cut off an attic room 21 of a building and the external walls 14 from the outside air by way of wrapping them with an air layer, to prevent rise of temperature of the attic room 21 and the external walls 14 due to radiant heat and to prevent dew condensation.