Disclosed herein is a secondary battery constructed in a structure in which pluralities of electrode tabs, protruding from an electrode assembly, are connected to corresponding electrode leads, and the electrode assembly is mounted in a receiving part, wherein a battery case is multi-formed, such that the battery case presses the upper end of the electrode assembly by a predetermined width, thereby preventing the upward movement of the electrode assembly, mounted in the receiving part, at the upper end space region of the receiving part, where the electrode assembly is spaced apart from the upper end of the receiving part, for the connection between the electrode tabs and the corresponding electrode leads, during the repetitive charge and discharge of the battery. Consequently, it is possible to prevent the occurrence of a short circuit of the battery due to external impacts, such as the dropping of the battery, and to prevent the occurrence of an internal short circuit of the battery due to the expansion of the battery case caused by the repetitive charge and discharge of the battery, whereby the safety of the secondary battery is improved.