NOVELTY - The secondary battery has flat wound electrode assembly (14) which includes positive electrode plate with positive electrode substrate, and a flat wound electrode assembly which includes the wound positive electrode substrate exposed portion (15) formed on one end portion. A negative electrode substrate exposed portion (16) is converged on a central site in the thickness direction of flat wound electrode assembly. A separator (13) located on the outermost surface and the negative electrode substrate exposed portion are fixed integrally with a fixing member.    USE - Secondary battery, e.g. lithium ion secondary batteries or nickel-hydrogen secondary batteries used as driving power sources for mobile electronic apparatus such as contemporary mobile telephones, portable personal computers, and portable music players. Can also be used as power sources for hybrid electric vehicles (HEVs) and electric vehicles (EVs).    ADVANTAGE - Prevents the semi-floating and peeling of the negative electrode active material mixture layer from occurring at the end side of negative substrate exposed portion since the separator and negative electrode substrate exposed portion of adjacent negative electrode plate are fixed integrally with a fixing member. Suppresses further the semi-floating and peeling of negative electrode active material mixture layer since the fixing member which serves as semi-floating prevention unit is provided to each both faces of flat wound electrode assembly. Improves the production efficiency since the positioning of the connection of negative electrode collector to the negative electrode terminal can be simplified. Obtains secondary batteries with higher reliability since the peeling off of the negative electrode active material mixture layers is prevented during the production of batteries, and the introduction of conductive foreign materials into batteries is suppressed.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a flat wound electrode assembly.    Separator (13)    Flat wound electrode assembly (14)    Positive electrode substrate exposed portion (15)    Negative electrode substrate exposed portion (16)    Semi-floating prevention tape (35)