To provide an apparatus and a method for molding a glass optical element without causing air trap, not requiring a large-scale pressure unit in molding the glass optical element.

In this apparatus for molding a glass optical element having a molding vacuum chamber 1 for taking in and out a molding mold 12 composed of a pair of an upper mold 10 an a lower mold 11 and a pressure bar 5 which is inserted into the upper wall of the chamber 1 and vertically slidable, the chamber 1 is a vacuum chamber and the vacuum chamber has a flexible upper wall 8. The pressure bar 5 is fixed to the flexible upper wall 8 and is vertically movable together with the upper wall.