Abstract: This application relates to the field of injection technology, especially a type of portable carbon dioxide gas injector. The technical solution of the invention includes a storage tube, one end of which is connected with a passage tube, and a passage valve is provided at the end of the passage tube away from the storage tube. A piston adapted to the injection device body is arranged inside the storage tube. A driving assembly for driving the piston is arranged on one side of the piston away from the passage tube, and a regulating assembly for adjusting the gas storage volume is arranged on the other side of the driving assembly away from the passage tube. The invention achieves quantitative control of the injection amount of carbon dioxide, which can alleviate the discomfort of patients.