A rectangular nonaqueous electrolyte secondary battery includes a positive electrode (11) and a negative electrode (12) wound with a porous insulating layer (13) interposed therebetween. The positive electrode (11) includes a positive electrode current collector (11A), and a positive electrode material mixture layer (11B). The positive electrode material mixture layer (11B) is provided on each of surfaces, or one of surfaces of the positive electrode current collector (11A), contains a positive electrode active material and a binder, and has a porosity of 17% or lower. The positive electrode (11) has a tensile strength of 15 N/cm or lower when a tensile extension of the positive electrode is 1%. A peel strength between the positive electrode current collector (11A) and the positive electrode material mixture layer (11B) is 3 N/m to 15 N/m, both inclusive.