A battery module and a flat battery cell that can reduce the man-hours required for connecting flat battery cells and eliminate the necessity of providing increased strength and enhanced insulation against vibration and other external forces. A stacked structure is obtained by stacking unidirectionally oriented structures (20-1 to 20-3) for a laminated battery cell (20) that is formed by bending a positive electrode terminal (23) and a negative electrode terminal (22), which are respectively extended from the end faces of a battery element (21), over different flat surfaces of the battery element (21) . Further, one polarity terminal of one of opposing neighboring laminated battery cells is in partial planar contact with a polarity terminal that belongs to the other one of the opposing neighboring laminated battery cells (20) and has a polarity opposite to the polarity of the one polarity terminal. Furthermore, each laminated battery cell (20) having the stacked structure is fixed by applying vertical pressure to the contact surface of the polarity terminal with a pressing mechanism.