A battery pack that can prevent deformation caused by external impact as well as leakage of an electrolyte. The battery pack includes a bare cell including a pouch type casing, an electrode assembly accommodated in the pouch type casing, and positive and negative electrode tabs extending from one side of the pouch type casing, a protection circuit board electrically connected to the bare cell, and a main body accommodating the bare cell and the protection circuit board. The battery pack also includes at least one reinforcing plate, wherein ends of the reinforcing plate are in contact with a surface of a front end portion of the bare cell or an inner surface of the main body. The reinforcing plate can be formed integrally with an upper or lower case of the main body or can be formed separately and disposed in the upper case or lower case.