A gas bottle comprising: - a sealed container, filled with said gas and provided, on its upper wall, with a pierceable portion for allowing the supply of gas to an external user device; and - a safety valve positioned inside said container so as to at least limit the outflow of gas towards said pierceable portion when said container is not connected to said user device; said valve being made entirely of an elastically deformable material, having a longitudinal axis and comprising a fixed part and a movable part both being together a single component; said fixed part comprising an annular flange fixed to the inside of said container; said movable part extending in a cantilever fashion from said flange and being elastically mobile in respect thereto along the said axis; said movable part comprising: - a sealing portion arranged in a radially innermost position in respect to said flange, elastically loaded in a first direction along said axis for cooperating, in use, against said upper wall of said container around said pierceable portion so as to define a normal sealing condition, wherein at least the outflow of gas towards the pierceable portion itself is limited, and movable, in use, upon the action of an external thrust exerted by said user device, in a second direction along said axis, opposite to said first direction, to define a condition of opening, wherein said sealing portion is axially spaced from said upper wall of said container; and - a plurality of petals equally spaced angularly from one another around said axis, delimiting respective through windows between one another and connecting said flange to said sealing portion; characterized in that said flange of said valve is fixed to said upper wall of said container around said pierceable portion at the peripheral edge of said pierceable portion or at the annular area immediately surrounding the pierceable portion itself. - a sealed container, filled with said gas and provided, on its upper wall, with a pierceable portion for allowing the supply of gas to an external user device; and - a safety valve positioned inside said container so as to at least limit the outflow of gas towards said pierceable portion when said container is not connected to said user device; said valve being made entirely of an elastically deformable material, having a longitudinal axis and comprising a fixed part and a movable part both being together a single component; said fixed part comprising an annular flange fixed to the inside of said container; said movable part extending in a cantilever fashion from said flange and being elastically mobile in respect thereto along the said axis; said movable part comprising: - a sealing portion arranged in a radially innermost position in respect to said flange, elastically loaded in a first direction along said axis for cooperating, in use, against said upper wall of said container around said pierceable portion so as to define a normal sealing condition, wherein at least the outflow of gas towards the pierceable portion itself is limited, and movable, in use, upon the action of an external thrust exerted by said user device, in a second direction along said axis, opposite to said first direction, to define a condition of opening, wherein said sealing portion is axially spaced from said upper wall of said container; and - a plurality of petals equally spaced angularly from one another around said axis, delimiting respective through windows between one another and connecting said flange to said sealing portion; - a sealing portion arranged in a radially innermost position in respect to said flange, elastically loaded in a first direction along said axis for cooperating, in use, against said upper wall of said container around said pierceable portion so as to define a normal sealing condition, wherein at least the outflow of gas towards the pierceable portion itself is limited, and movable, in use, upon the action of an external thrust exerted by said user device, in a second direction along said axis, opposite to said first direction, to define a condition of opening, wherein said sealing portion is axially spaced from said upper wall of said container; and - a plurality of petals equally spaced angularly from one another around said axis, delimiting respective through windows between one another and connecting said flange to said sealing portion; characterized in that said flange of said valve is fixed to said upper wall of said container around said pierceable portion at the peripheral edge of said pierceable portion or at the annular area immediately surrounding the pierceable portion itself.