NOVELTY - The battery (C) has a positive electrode terminal board (3) consisting of an electroconductive board material, and a negative electrode terminal board (5) arranged opposing in parallel with other terminal board. A rectangular frame (7) consisting of insulating materials is fixed to the boards to form the outer periphery of casing (9). The terminal boards are located inside the frame, in vertical and horizontal directions of the battery. Each outer edge of the board is formed as the insert molding object joined to the frame in fluid-tight manner.    USE - Sealed square battery mounted in vehicles such as motor vehicle and electric train.    ADVANTAGE - The sealing property with a battery is securable by fluid-tightly joining the frame and the boards by insert molding. Since the terminal boards are located inside the frame, an external short circuit does not occur easily. Therefore, the assembly operation and handling of the battery can be carried out easily. The need for providing a sealing element and an external short circuit prevention element in the battery module can be excluded, and a structure can be simplified, so that the weight and volume can be reduced significantly. The energy density of the battery module is improved, and a battery module can be accommodated in a narrow installation space. The contact state of each terminal board and an electrode becomes favorable, so that internal resistance of a battery can be reduced and the battery performance can be improved. The positioning of terminals board and electrode can be carried out correctly hence the reliability of a battery can be improved. The deformation of the terminal boards in the opposition direction, vertical direction and horizontal direction by the battery's internal pressure can be prevented, the pressure resistance of a battery can be improved and the fall of battery life can be prevented. Sufficient long-term charge and discharge performance of the battery is securable. The structures for tightening and insulation can be excluded in the battery module, so that structure of the battery can be further simplified and its weight and volume can be reduced significantly. A battery can be manufactured easily and the dimension variation between batteries is suppressed.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for assembling method of sealed square battery.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the sealed square battery.    Positive electrode terminal board (3)    Negative electrode terminal board (5)    Rectangular frame (7)    Casing (9)    Sealed square battery (C)