Shut-off device for a gas tank apparatus , comprising a first connector for connection to a high-pressure tank and a second connector for connection to a supply line , a main valve chamber , which has a first opening connected to the first connector in a fluidically conductive manner, a second opening connected to the second connector in a fluidically conductive manner, and a first control opening , and a main valve , which is designed as a switchable solenoid valve and has a main valve needle arranged in the main valve chamber , which can be moved between a closed position, in which it bears against a main valve seat surrounding the second opening in order to seal the second opening with respect to the first opening , and an open position, in which it is lifted from the main valve seat, wherein the main valve needle divides the main valve chamber into an outlet chamber , into which the first and the second opening open, and a control chamber , into which the first control opening opens and which is connected to the outlet chamber in a fluidically conductive manner, wherein the shut-off device has a servo valve chamber spatially separated from the main valve chamber , which comprises a second control opening connected to the first control opening in a fluidically conductive manner and a servo opening connected to the second connector in a fluidically conductive manner, characterized in that the shut-off device has a servo valve , which is designed as a switchable solenoid valve, having a servo valve needle arranged in the servo valve chamber , which can be moved between a closed position, in which it bears against a servo valve seat surrounding the servo opening in order to seal the servo opening with respect to the second control opening , and an open position, in which it is lifted from the servo valve seat. and a main valve , which is designed as a switchable solenoid valve and has a main valve needle arranged in the main valve chamber , which can be moved between a closed position, in which it bears against a main valve seat surrounding the second opening in order to seal the second opening with respect to the first opening , and an open position, in which it is lifted from the main valve seat, wherein the main valve needle divides the main valve chamber into an outlet chamber , into which the first and the second opening open, and a control chamber , into which the first control opening opens and which is connected to the outlet chamber in a fluidically conductive manner, wherein the shut-off device has a servo valve chamber spatially separated from the main valve chamber , which comprises a second control opening connected to the first control opening in a fluidically conductive manner and a servo opening connected to the second connector in a fluidically conductive manner, characterized in that the shut-off device has a servo valve , which is designed as a switchable solenoid valve, having a servo valve needle arranged in the servo valve chamber , which can be moved between a closed position, in which it bears against a servo valve seat surrounding the servo opening in order to seal the servo opening with respect to the second control opening , and an open position, in which it is lifted from the servo valve seat. <EOS>