PURPOSE: To enable one to escape safely out of the a building in a short time by sending gas to an escape member stored in a storage, and expanding an escape opening.

CONSTITUTION: This device is provided with a groove 12, in the vicinity of the window outside the wall of a building where a window frame 10 is attached, and this is provided with a chute 16 which is stored in the groove 12, being folded therein, with one end attached to the groove 12, and expands when gas is injected and forms an escape path capable of sliding down, with the other end extending onto the ground. This is provided with decorative boards 13, 14, and 15, which cover the groove when the chute 16 is stored and are separated from the groove 12 by the expanded chute 16, and, inside the wall where time window is attached, a bomb, which accumulate gas and injects gas into the chute 16 in an emergency. When gas is injected into the escape member from the bomb, the escape member expands, and the escape member extends, for example, onto the ground, and forms an escape path capable of sliding down, and one can escape out of a building, sliding down the escape member from the window.