A nonaqueous electrolyte secondary battery includes an electrode group 8 including a positive electrode 4 including a positive electrode current collector 4A and a positive electrode active material formed on the positive electrode current collector 4A, a negative electrode 5 including a negative electrode current collector 5A and a negative electrode active material formed on the negative electrode current collector 5A, and a porous insulating layer 6, the electrode group 8 being formed by winding or stacking the positive electrode 4 and the negative electrode 5 with the porous insulating layer 6 interposed. The positive electrode 4 has a tensile extension equal to or higher than 3.0%. The porous insulating layer 6 is made of a material containing aramid resin. Hence, even when the nonaqueous electrolyte secondary battery is destroyed by crush, occurrence of an internal short circuit in the battery can be prevented, thereby suppressing abnormal heat generation caused by an internal short circuit.