The present invention pertains to a device for producing and a method for producing a secondary battery. Secondary batteries are produced by interposing a separator between positive and negative electrode plates, but conventionally, the separators are sandwiched by a pair of rollers, the rollers are caused to reciprocate in the horizontal direction, the separator is folded in a zig-zag fashion, and the positive and negative electrode plates are alternatingly placed on the separator each time the pair of rollers reciprocate, and so there has been the problem that it has been difficult to greatly reduce takt time. The present invention resolves the problem for example by method having: a step for pressing a separator (4) by means of a plurality of guide members (21), folding the separator in a zig-zag fashion; a step for forming a layered body having alternatingly overlapping positive electrode plates and negative electrode plates by alternatingly inserting a positive electrode plate (5) and negative electrode plate (6) in each furrow of the zig-zag folded separator with the separator therebetween; a step for removing the guide members from within each furrow of the separator; and a step for pressing the layered body in the direction of layering; the step for folding in a zig-zag fashion being performed after causing the separator to be in a tension-free state.