a reservoir for storing a pressurized fluid is disclosed , having a longitudinal axis and comprising a central tubular portion closed at its ends by two bottoms , one at least of which bulges outwardly and is provided with a neck , and also a method of manufacturing such a reservoir . according to the invention , said reservoir is formed by a tubular shell of a composite fiber - thermoplastic binder material and two end pieces made from a thermoplastic material strengthened with reinforcement fibers , said shell and said end pieces being secured solidly together by local heat - melted zones .