The invention provides a gas charging and discharging device, and relates to the technical field of gas charging and discharging devices. The gas charging and discharging device comprises a pushing rod and a joint blocking part, wherein the pushing rod is provided with a pushing rod initial position which is spaced with a valve element, and a pushing rod self-locking position which is jacked and matched with the valve element, and is kept in a self-locking state; an operating mechanism for pushing the pushing rod to switch between the pushing rod initial position and the pushing rod self-locking position is arranged on the pushing rod; the operating mechanism comprises a pushing rod hinged part which is hinged with the pushing rod, and a self-locking connecting rod which is separately hinged with the joint blocking part and the pushing rod hinged part; a hinge axis for the pushing rod hinged part and the self-locking connecting rod and a hinge axis for the pushing rod hinged part and the pushing rod are arranged in a spaced mode in parallel; and a connecting line for two hinge points, which are separately hinged with the joint blocking part and the pushing rod hinged part, on the self-locking connecting rod is parallel to a length direction of the pushing rod while the pushing rod is in the pushing rod self-locking position, so that the pushing rod is kept in the self-locking state. The pushing rod is kept in the self-locking state to prevent the valve element from rebounding and returning, so that the problem that operation wastes time and labor while gas charging and discharging operation is performed on a gas chamber is solved.