An apparatus for molding a pouch, the pouch having a first seating part and a second seating part, that are connected to each other, the pouch being configured such that when an electrode assembly is mounted and sealed therein, the first seating part and the second seating part are folded to cover top and bottom surfaces of the electrode assembly, and the first seating part and the second seating part are in contact with each other. The apparatus includes, a lower mold in which a first groove recessed by a predetermined depth from a top surface thereof is formed, and a second groove is additionally recessed from a bottom surface of the first grove; and an upper mold on which a flat portion is formed on one surface thereof, which is inserted into the first groove, and a protrusion inserted into the second groove protrudes from the flat portion.