A secondary battery includes an electrode assembly; a case accommodating the electrode assembly; a cap plate coupled to a top portion of the case; an electrode terminal electrically connected to the electrode assembly and including a terminal pillar passing through the cap plate, and an extension part extending horizontally from a top end of the terminal pillar; a terminal plate electrically connected to the electrode terminal; an insulation member between the terminal plate and the cap plate; and a fuse part defined by a portion of the extension part and the terminal plate that are welded to each other and located on the insulation member.