A battery pack includes a non-aqueous electrolyte secondary battery, a rigid covering member, and a protection circuit board. The secondary battery includes a battery element and a flexible covering member formed of a first laminated film composed of a first heat-bonding layer, a first metal layer, and a first outer covering layer which are laminated successively. The flexible covering material is sealed along around the battery element while leaving electrode terminals of the positive and negative electrodes extended outside the battery element. The rigid covering member covers the non-aqueous electrolyte secondary battery together with the flexible covering member, and is formed of a second laminated film composed of a second heat-bonding layer, a second metal layer, and a second outer covering layer which are laminated successively.; The flexible covering member and the rigid covering member are bonded by melting the second heat-bonding layer without melting the first outer covering layer.