The present invention relates to an apparatus for molding a glass substrate, and more specifically, to an apparatus for molding a glass substrate capable of forming a glass substrate in a 3D shape and preventing the shape of a vacuum hole from transferring onto the surface of the substrate. To this end, the present invention provides the apparatus for shaping a glass substrate, comprising: a molding frame having a cavity, at least one vacuum hole and at least one decompression hole, wherein the cavity disposed on one surface of the molding frame, the at least one vacuum hole formed in the molding frame below the cavity, the at least one vacuum hole being connected to an external vacuum device, and the at least one decompression hole defined between the cavity and the at least one vacuum hole such that the cavity communicates with the at least one vacuum hole, wherein a width of the at least one decompression hole is greater than a width of the at least one vacuum hole such that the at least one decompression hole lessens vacuum pressure applied to the glass substrate disposed on the cavity through the at least one vacuum hole, wherein all of the at least one vacuum hole are connected to the at least one decompression hole.