A metal foil bonding device (50) for bonding pieces of metal foil (2) on the successively conveyed sheet-shaped electrodes (1) on the conveyor plates (20) is provided. When it is detected that there is an abnormality in a piece of metal foil (2) to be bonded to the sheet-shaped electrode (1) on the conveyor plate (20) next conveyed to the metal foil bonding device (50), the conveyor plate (20) next conveyed to the metal foil bonding device (50) is temporarily stopped right before the metal foil bonding device (50).