Pressure regulator, comprising: - a device for regulating the pressure of a fluid and a main body having an inlet for receiving the fluid, a circumferential wall delimiting a housing for receiving the regulating device and an outlet for distributing the fluid, the regulating device being positioned in the housing between the inlet and the outlet and having: - a seat body defining an orifice for passage of the fluid, - a valve which can move relative to the seat body along a central axis of the seat body between a closed position, in which the valve closes the orifice, and an open position, in which the valve uncloses the orifice, - a membrane which is mechanically fixedly attached to the valve, - a spring for causing the membrane to bear against the seat body, able to exert a bearing force on the membrane, the membrane beings able to move relative to the seat body between an open position, in which the membrane defines with the seat body a space for passage of the fluid having passed through the passage orifice, able to guide the fluid to the outlet, and a closed position, in which the membrane is in sealing contact with the seat body and closes the passage space, and - a member for setting the pressure of the fluid, the setting member comprising a base comprising a contact wall extending radially with respect to the central axis and in contact with the spring, the spring being positioned between the membrane and the contact wall, characterised in that the setting member comprises a part for setting the position of the base relative to the seat body, the setting part defining at least two positions for holding the base relative to the seat body which are offset with respect to each other along the central axis and corresponding to at least two different positions of the contact wall relative to the seat body, and in that the base comprises a skirt extending along the central axis and arranged between the circumferential wall and the seat body, and in that for one of the positions for holding the base the skirt defines with the circumferential wall or the seat body a space for circulation of fluid connecting the inlet to the outlet. - a device for regulating the pressure of a fluid and a main body having an inlet for receiving the fluid, a circumferential wall delimiting a housing for receiving the regulating device and an outlet for distributing the fluid, the regulating device being positioned in the housing between the inlet and the outlet and having: - a seat body defining an orifice for passage of the fluid, - a valve which can move relative to the seat body along a central axis of the seat body between a closed position, in which the valve closes the orifice, and an open position, in which the valve uncloses the orifice, - a membrane which is mechanically fixedly attached to the valve, - a spring for causing the membrane to bear against the seat body, able to exert a bearing force on the membrane, the membrane beings able to move relative to the seat body between an open position, in which the membrane defines with the seat body a space for passage of the fluid having passed through the passage orifice, able to guide the fluid to the outlet, and a closed position, in which the membrane is in sealing contact with the seat body and closes the passage space, and - a member for setting the pressure of the fluid, the setting member comprising a base comprising a contact wall extending radially with respect to the central axis and in contact with the spring, the spring being positioned between the membrane and the contact wall, characterised in that the setting member comprises a part for setting the position of the base relative to the seat body, the setting part defining at least two positions for holding the base relative to the seat body which are offset with respect to each other along the central axis and corresponding to at least two different positions of the contact wall relative to the seat body, and in that the base comprises a skirt extending along the central axis and arranged between the circumferential wall and the seat body, and in that for one of the positions for holding the base the skirt defines with the circumferential wall or the seat body a space for circulation of fluid connecting the inlet to the outlet.