Abstract: A pressure fluid reservoir for supplying pressure fluid to a wheel slip regulating device that is accommodated in a vehicle has a hose membrane that can be partially emptied by suction. The degree of emptying is limited due to the installation of an inner support body that fluid can flow through. The radial expansion of the hose membrane is limited by an outer support element and by a porous casing encompassing the outer support element, which protects the pressure fluid reservoir from bursting in the event that the hose membrane is subjected to brake pressure. The inner support element, the outer support element, and the casing are flexible hoses and are connected in a pressure-tight fashion to tube line connections in such a way that the pressure fluid reservoir according to the invention is placed in the vehicle in the same way as a brake line.