A fully solid battery includes a positive electrode plate, a solid electrolyte layer disposed on one side of the positive electrode plate, a negative electrode plate disposed on one side of the solid electrolyte layer, and a buffer film disposed on one side of the negative electrode plate. The buffer film includes a base substrate and a buffer layer on at least one surface of the base substrate. The buffer layer includes a first particulate that provides resilience, a second particulate that relieves stress, and a binder.