A gas turbine combustion chamber system, in particular micro gas turbine combustion chamber system, comprising: - a combustion chamber which has a longitudinally extending flame tube surrounding a flame zone, which is provided with a burner on its inlet side and is coupled or can be coupled to a turbine arrangement on its outlet side facing away therefrom, and is provided with mixed air openings in an outlet section, - comprising a pressure housing surrounding the combustion chamber, between the inner side of which and the outer side of the flame tube for supplying an air mass flow, an inflow channel is formed leading from its outlet side to the inlet side, via which a mixed air portion is guided via the mixed air openings into the interior of the flame tube, and a burner air portion is supplied to the burner for combustion with the inflowing fuel, and - comprising a control device via which the burner air portion supplied to the burner can be controlled by varying the mixed air portion depending on the load point of the turbine arrangement by adjusting the clear flow width of the mixed air openings, wherein - the control device has an actuating device which responds to a pressure difference (Δp) between the inflow channel of the air and the surroundings of the combustion chamber system, by means of which the clear flow width of the mixed air openings is reduced depending on the load point, in particular continuously, with an increasing load point and increased with a decreasing load point, and - the actuating device is mechanically constructed, wherein the pressure difference (Δp) is used indirectly or, in particular, directly as a drive source - when using the pressure difference (Δp) as an indirect drive source, an actuating unit with a pressure sensor, a converter unit and at least one actuator driven by the latter is present, by means of which the clear flow width of the mixed air openings can be varied via a closing unit, and when using the pressure difference (Δp) as a direct drive source, the at least one actuator itself is designed as a pressure sensor, by means of which the clear flow width of the mixed air openings can be varied via the closing unit; characterized in that - the actuating device has as at least one actuator, a bellows, in particular made of metal, which is firmly connected with its one end region to the pressure housing, and with its other end region spaced apart in the longitudinal direction is connected at a connecting portion via at least one intermediate link to the closing unit comprising at least one closing element, and - the interior of the bellows is connected to the air inflow channel via at least one pressure equalization channel. - a combustion chamber which has a longitudinally extending flame tube surrounding a flame zone, which is provided with a burner on its inlet side and is coupled or can be coupled to a turbine arrangement on its outlet side facing away therefrom, and is provided with mixed air openings in an outlet section, - comprising a pressure housing surrounding the combustion chamber, between the inner side of which and the outer side of the flame tube for supplying an air mass flow, an inflow channel is formed leading from its outlet side to the inlet side, via which a mixed air portion is guided via the mixed air openings into the interior of the flame tube, and a burner air portion is supplied to the burner for combustion with the inflowing fuel, and - comprising a control device via which the burner air portion supplied to the burner can be controlled by varying the mixed air portion depending on the load point of the turbine arrangement by adjusting the clear flow width of the mixed air openings, - the control device has an actuating device which responds to a pressure difference (Δp) between the inflow channel of the air and the surroundings of the combustion chamber system, by means of which the clear flow width of the mixed air openings is reduced depending on the load point, in particular continuously, with an increasing load point and increased with a decreasing load point, and - the actuating device is mechanically constructed, wherein the pressure difference (Δp) is used indirectly or, in particular, directly as a drive source - when using the pressure difference (Δp) as an indirect drive source, an actuating unit with a pressure sensor, a converter unit and at least one actuator driven by the latter is present, by means of which the clear flow width of the mixed air openings can be varied via a closing unit, and when using the pressure difference (Δp) as a direct drive source, the at least one actuator itself is designed as a pressure sensor, by means of which the clear flow width of the mixed air openings can be varied via the closing unit; - the actuating device has as at least one actuator, a bellows, in particular made of metal, which is firmly connected with its one end region to the pressure housing, and with its other end region spaced apart in the longitudinal direction is connected at a connecting portion via at least one intermediate link to the closing unit comprising at least one closing element, and - the interior of the bellows is connected to the air inflow channel via at least one pressure equalization channel.