The present invention relates to a glass substrate forming apparatus and, more particularly, to a glass substrate forming apparatus that can form a three-dimensionally-shaped glass substrate having various curved surfaces and curvatures without restrictions in terms of the number of curved surfaces and the sizes of the curvatures of the curved surfaces - that is, a three-dimensional glass substrate having at least one side of four sides formed in a curvature and having one of various designs. To this end, the present invention provides a glass substrate forming apparatus characterized by comprising: a molding frame; a forming recess formed in one surface of the molding frame; a plurality of vacuum holes formed in the molding frame and communicating with the forming recess; and a vacuum unit connected to the plurality of vacuum holes, wherein a plurality of vacuum holes are formed into groups for the respective regions of the forming recess and are divided into a plurality of vacuum hole groups, and when individually connected with each of the plurality of vacuum hole groups to form a glass substrate, the vacuum unit sequentially applies vacuum pressure for each region of the glass substrate.