The disclosed non-aqueous electrolyte secondary battery is provided with an electrode body formed by superimposing a positive electrode sheet and a negative electrode sheet (20) separated by a separator sheet (40), wherein between the separator sheet (40) and the positive electrode sheet and/or the negative electrode sheet (20), a porous layer (42) is formed having filler particles (44) and a binder, and the median value in the circularity distribution of the filler particles (44) contained in the porous layer (42) is 0.85-0.97.