PURPOSE: To obtain a double-layered covering material having a gas-flowing mechanism capable of sufficiently receiving the sunlight radiation and lowering the quantity of heat penetrated into or lost from a room by the heat-conduction through the covering material and to provide a room equipped with the double- layered covering material.

CONSTITUTION: This covering material 1 is composed of two transparent boards 2 and 3 arranged to form a double layer by placing one on the other with a gap. A header 11 for diffusing inlet gas is installed on an end face of the placed transparent boards 2 and 3 to spontaneously or forcibly flow the gas into the gap of the covering material 1, a pipe 12 is set to the header 11, a slit 13 is formed on an end face of the header 11 and a slit 14 for a gas-ejecting path is formed on the other end side of the transparent board 2.