Gas Removing Device and Method of Secondary Battery

The present invention provides a gas removing device, which removes a gas generated inside a pouch, in which an electrode assembly is accommodated. The gas removing device includes a pair of vacuum tubes configured to press opposing surfaces of a pouch so as to form a vacuum surface on the pouch; a heating member provided on a pressing surface of each of the vacuum tubes, which presses the pouch, is configured to seal only a portion of an edge of the vacuum surface so as to form a sealed part and an unsealed part; a cutting member configured to cut the vacuum surface of the pouch and form a cutoff hole; and a gas discharging member configured to discharge a gas from inside the pouch to the outside through the unsealed part, the cutoff hole, and the vacuum tubes.