To improve the safety of a flat secondary battery module suitable for large current charging and discharging that is used as a power supply for an electric vehicle, etc.

The flat secondary battery module comprises a plurality of stacked unit cells and a current blocking unit, wherein the current blocking unit has an electric path blocking mechanism that blocks an electric path by using an expansion force of an adjacent unit cell adjacent to the current blocking unit, and the unit cells are flat. In the flat secondary battery module, a bypass circuit that is connected in parallel to each of the unit cells and has a bypass resistance section and a switch section and a charge/discharge control unit having a bypass control and output section are provided. The switch section is connected to the bypass control and output section and the charge/discharge control unit has a unit cell voltage detection unit for detecting a terminal voltage of each unit cell. The bypass control and output unit controls the open/close of the switch section in such a manner that the remaining capacity of the adjacent unit cell may be larger than that of the other unit cells.