A positive electrode, a negative electrode, and a non-aqueous electrolyte. The negative electrode includes a negative electrode material, a binder, and a thickener, and the negative electrode material includes a lithium silicate phase, and Si particles dispersed in the lithium silicate phase. The ratio of the Si particles in the negative electrode material is 30 mass % or more. The binder includes a poly(meth)acrylic acid, the thickener includes a carboxyalkyl cellulose, and the amount of the poly(meth)acrylic acid relative to 100 parts by mass of the negative electrode material is 0.1 parts by mass or more and 5 parts by mass or less. The non-aqueous electrolyte includes a lithium salt, a non-aqueous solvent, and an acid that exhibits a pKa of 1 to 30 in water at 25° C. The non-aqueous electrolyte secondary battery can suppress the generation of gas during high-temperature storage, and secure excellent cycle characteristics.