Nowadays in aircraft on-board inert gas generation systems (OBIGGS) are used to generate inert gases. Cooled bleed air of engines or auxiliary turbines is fed to said OBIGGS systems. According to an embodiment of the present invention, an air supply device for an OBIGGS system in an aircraft is proposed that comprises a bleed position (1,2). By way of the bleed position (1,2), air from an air conditioning unit (4,5) on board the aircraft can be bled and can be fed to the OBIGGS system. There is thus no need for an additional heat exchanger and an additional ram-air channel. Maintenance expenditure and air resistance are thus reduced.