A battery pack comprising: a plurality of non-aqueous electrolyte single cells, each single cell being housed in a flat case, and having a rolled electrode body in which a positive electrode sheet, a negative electrode sheet, and a separator sandwiched therebetween are flatly rolled; a plurality of spacers that are juxtaposed in a predetermined direction alternately with the plurality of single cells; and a banding member (5; 7) that applies pressure in the predetermined direction to a juxtaposed body that includes the plurality of single cells and the plurality of spacers, and bands the juxtaposed body together, wherein the rolled electrode body includes a collector portion (17; 18) provided on both ends in a rolling axis direction, and a power generating portion positioned between the collector portion (17; 18) on both ends; each spacer has at least one recessed portion provided on at least one surface that faces the single cell adjacent to the spacer; and characterized in that a side plate of the case that faces the surface of the spacer on which the recessed portion is provided includes a thick portion that contacts the power generating portion of the rolled electrode body inside the case, and a thin portion that is thinner than the thick portion and is continuous with both sides of the thick portion in the rolling axis direction, each spacer having a size such that a planar shape thereof is smaller than the thick portion, the planar shape being the shape of a surface when viewed in the predetermined direction, and the surface of the spacer on which the recessed portion is provided abuts against the thick portion only. a plurality of non-aqueous electrolyte single cells, each single cell being housed in a flat case, and having a rolled electrode body in which a positive electrode sheet, a negative electrode sheet, and a separator sandwiched therebetween are flatly rolled; a plurality of spacers that are juxtaposed in a predetermined direction alternately with the plurality of single cells; and a banding member (5; 7) that applies pressure in the predetermined direction to a juxtaposed body that includes the plurality of single cells and the plurality of spacers, and bands the juxtaposed body together, wherein the rolled electrode body includes a collector portion (17; 18) provided on both ends in a rolling axis direction, and a power generating portion positioned between the collector portion (17; 18) on both ends; each spacer has at least one recessed portion provided on at least one surface that faces the single cell adjacent to the spacer; and characterized in that a side plate of the case that faces the surface of the spacer on which the recessed portion is provided includes a thick portion that contacts the power generating portion of the rolled electrode body inside the case, and a thin portion that is thinner than the thick portion and is continuous with both sides of the thick portion in the rolling axis direction, each spacer having a size such that a planar shape thereof is smaller than the thick portion, the planar shape being the shape of a surface when viewed in the predetermined direction, and the surface of the spacer on which the recessed portion is provided abuts against the thick portion only.