To provide a non-aqueous electrolyte electricity-storage element including a positive electrode including a positive-electrode active material capable of inserting and releasing anions, a negative electrode including a negative-electrode active material capable of inserting and releasing cations, and a non-aqueous electrolyte, wherein the positive-electrode active material is porous carbon having pores having a three-dimensional network structure, and wherein a changing rate of a cross-sectional thickness of a positive electrode film including the positive-electrode active material defined by Formula (1) below is less than 45%.