A battery (1) with an outer film cover, where a battery element (2) is surrounded by laminated films (5, 6). In the battery element (2), positive and negative electrode extension sections (2a, 2b) are joined to positive and negative electrode leads (3a, 3b), respectively and collectively. The laminated films (5, 6) are each formed by layering on each other at least a heat bonding layer (10) and a metal layer (11). A protective member (4a) having lower melting point than the heat bonding layer (10) is placed between a joint (20a, 20b) of at least the positive/negative electrode extension section (2a, 2b) and the heat bonding layer (10), facing the joint, of the laminated film (5).