A non-aqueous electrolytic solution secondary battery includes: a positive electrode; a negative electrode; a separator that separates the positive electrode and the negative electrode from each other; and an electrolytic solution that is introduced into the non-aqueous electrolytic solution secondary battery so as to come into contact with the positive electrode and the negative electrode with the separator interposed therebetween, wherein the electrolytic solution contains an electrolyte and a phosphazene compound in an aprotic solvent, and the separator is a complex that is composed of a substrate containing a non-heat-resistant resin and a heat-resistant material coating the substrate.