Abstract: An air supply device which may be used for emergencies such as an escape from a buring building comprises an air tank having a hose connected to a face mask and an activation element and a regulation element. The activation element consists of a spring biased valve which will automatically move to an opened position when a holding pin is released. The regulation element consists of a U-shaped valve having a first end for covering apertures leading to the hose and a second end in engagement with an expansion element. As air is removed from the tank during use of the device, the expansion element will expand due to a decrease in air pressure within the tank. As the expansion element enlarges, the U-shaped valve will move so as to expose additional apertures. A constant supply of air is therefore easily and automatically maintained.