To provide a manufacturing method of a battery that can surely prevent short circuit between the electrodes even if vertical burrs appear at the sheet cut face.

When a positive electrode sheet 1 and a negative electrode sheet 2 which are cut in a prescribed dimension are overlapped holding a separator 3 in between, the edge of the separator 3 is folded back and the separator 3 is made a double layer structure at the corresponding part P of the cut out face 1A of the positive electrode sheet 1. In this state, each sheet 1 to 3 is overlapped and the vertical notches 4 which appeared on the cut out face 1A of the positive electrode sheet 1 is made not to contact with the negative electrode sheet 2.