Device for storing and for supplying fluid fuel, comprising a reservoir of liquefied fuel gas in equilibrium with a gas phase, in particular hydrogen, a circuit for filling the reservoir, at least one circuit for tapping fluid from the reservoir, and at least one circuit for regulating the pressure in the reservoir, the filling circuit, tapping circuit and pressure-regulating circuit comprising a set of valves arranged in a housing separate from the reservoir, the housing being removably connected to the reservoir via a demountable mechanical coupling system, the tapping circuit, the pressure-regulating circuit and the filling circuit comprising a set of demountable fluidic connectors situated at the junction between the reservoir and the housing and configured to allow the separation between portions of circuits situated in the reservoir and in the housing during the demounting of the housing with respect to the reservoir.