A method of manufacturing a rechargeable battery pouch having three sealed sides, an apparatus for manufacturing the same, and a rechargeable battery manufactured thereby in which a pouch film may be bent, and an uneven portion may then be formed in a bent portion by using a bending knife, thereby reducing a gap between a lower end of the pouch film and an electrode assembly when the electrode assembly is accommodated in the pouch film. In this manner, it is possible to reduce a size of a bat-ear shaped fold to increase a contact area between the battery pouch and a cooling plate, and improve a space efficiency of the rechargeable battery.