The utility model relates to a hexafluoropropane automatic fire extinguisher, belonging to the fire-fighting equipment technology, which comprises an extinguishing agent holding bottle, a controller, a nozzle and a fire detector. The signal output terminal of the fire detector is connected with the controller; the output terminal of the extinguishing agent holding bottle is connected to the nozzle by a pneumatic bottle head valve and an extinguishing agent transmission pipe. In addition the utility model also comprises a start-up steel bottle. The output control terminal of the controller is connected to the controlled terminal of an electromagnetic bottle head valve on the start-up steel bottle by a control wire. The output port of the electromagnetic bottle head valve is connected to the controlled terminal of the pneumatic bottle head valve by a start-up pipe. Because of the reasonable adoption of the controller to control the electromagnetic valve and the automatic control way by the start-up gas opening the extinguishing agent holding bottle, a gas fire extinguisher with the main physical fire extinguishing and the auxiliary less chemical fire extinguishing is used to improve the extinguishing effect with good electrical insulating property, rapid extinguishing and reliable performance but without defiling equipments.