A device for oxygen supply of a user in an aircraft comprising a breathing mask (20), a stowage box (1) for the breathing mask and an oxygen supply hose (22) having one end connected to the stowage box and the other end connected to the breathing mask, wherein the device further comprises means (3) to fix the stowage box in a ceiling of the aircraft, an aperture on the bottom side of the stowage box closed by a door (7) and a leash (28) connected to the stowage box by one end and to the breathing mask by the other end so that, when the door is open, the mask falls and is kept hovered by the oxygen supply hose and the leash.