A lithium secondary battery that is excellent in resistance to short-circuits and heat, is unlikely to suffer a capacity loss due to impact such as dropping, and has a high capacity. The lithium secondary battery includes an electrode assembly including a strip-like positive electrode and a strip-like negative electrode that are wound together with a porous heat-resistant layer interposed therebetween, a non-aqueous electrolyte, and a battery can. The battery has a restricting part for restricting vertical movement of the electrode assembly. The distance A from the restricting part to the inner bottom face of the battery can and the width B of the negative electrode satisfy the relation: 0.965≦B/A≦0.995.