Disclosed is a rectangular nonaqueous electrolyte secondary battery wherein a positive electrode (11) and a negative electrode (12) are wound up together with a porous insulating layer (13) interposed therebetween. The positive electrode (11) comprises a positive electrode collector (11A) and a positive electrode mixture layer (11B). The positive electrode mixture layer (11B) is provided on both surfaces or one surface of the positive electrode collector (11A), contains a positive electrode active material and a binder, and has a porosity of not more than 17%. The positive electrode (11) has a tensile strength of not more than 15 N/cm at 1% elongation. The peel strength between the positive electrode collector (11A) and the positive electrode mixture layer (11B) is 3-15 N/m (inclusive).