A battery includes: an electrode group including a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode; an electrolyte; a container for accommodating the electrode group and the electrolyte; a sealing member for blocking an opening in the container; and a first lead for electrically connecting the first electrode to the sealing member. The first lead has a weld region welded to the sealing member, and the weld region has at least one first bump along the longitudinal direction of the first lead. The cross section of the boundary between the weld region and a non-weld region on the first electrode side has a projecting shape corresponding to the bump.