The invention is to provide a means for achieving adequate charge /
discharge cycle characteristics in a non-
aqueous electrolyte secondary battery having
large capacity and a large area even when a mixture of a high-capacity Si material and a carbon material that swells little is used as a negative
electrode active material. A non-
aqueous electrolyte secondary battery in which the value of the ratioof the battery volume (the product of the thickness of the battery and the
projected area of the battery including a battery exterior body) with respect to the rated capacity is 10 cm<3> / Ah or less and the rated capacity is 3 Ah or more, said non-
aqueous electrolyte secondary battery comprising a power generation element that includes: a positive
electrode in which a positive
electrode active material layer including a positive electrode active material is formed on the surface of a positive electrode
current collector; a negative electrode in which a negative electrode active material layerincluding a negative electrode active material is formed on the surface of a negative electrode
current collector; and a separator. The non-aqueous
electrolyte secondary battery is characterized in that: the negative electrode active material layer contains a negative electrode active material represented by formula (1) alpha (Si material) and beta (carbon material) (in the formula, the Si material is one or more substances selected from the group consisting of Si-containing alloys and SiOx (x represents the number of
oxygen atoms satisfying the valence of Si) that is a mixture of amorphous SiO2 particles and Si particles, the carbon material is one or more substances selected from the group consisting of
graphite, hardly graphitizable carbon, and
amorphous carbon, alpha and beta representthe
mass% of the individual components in the negative electrode active material layer, 80 <= alpha + beta <= 98, 0.1 <= alpha <= 40, and 58 <= beta <= 97.9); and when a plurality of discretionary locations within the plane of the negative electrode active material layer are selected and the area ratios (%) of the Si material and the carbon material in the area of the
field of view in each of images of a cross section of the negative electrode active material layer are denoted respectively as S (%) and (100-S) (%), the difference between the maximum value and the minimum value of S is within5%.