The valve apparatus includes: a valve body whose one side is combined with the movable oxygen cylinder, which communicates with a discharge port at the other side thereof along a path from one side thereof lengthily therein, to thus discharge out the oxygen of the oxygen cylinder through the discharge port. An opening which opens outwards from an insertion space provided along the path, and a post valve which is installed at the other side of the valve body and controls discharge of oxygen through the discharge port from the oxygen cylinder according to operation of a lever. A charge adapter whose one side is detachably installed in the opening of the insertion space, which charges oxygen supplied from the outside into the oxygen cylinder when the post valve closes the path, and discharges oxygen of the oxygen cylinder through the discharge port when the post valve opens the path.