A secondary battery comprising: a strip-shaped first electrode plate having a plurality of first electrode tabs; a strip-shaped second electrode plate having a different polarity from that of the first electrode plate; a flat-shaped wound electrode assembly obtained by winding the first electrode plate and the second electrode plate with a strip-shaped separator therebetween; and a first electrode current collector connected with the plurality of first electrode tabs laminated, wherein the first electrode plate has a first electrode core body made of metal and a first electrode active material layer formed on the first electrode core body, and on a first end side of the first electrode plate on which the plurality of first electrode tabs are provided, a first protrusion protruding in a thickness direction of the first electrode core body from one surface of the first electrode core body is formed on the one surface of the first electrode core body except where the plurality of first electrode tabs are, a protrusion protruding in the thickness direction of the first electrode core body from the other surface of the first electrode core body is not formed on the other surface of the first electrode core body, or a second protrusion protruding in the thickness direction of the first electrode core body from the other surface of the first electrode core body and having a smaller protrusion height than a protrusion height of the first protrusion is formed on the other surface of the first electrode core body, the protrusion height of the first protrusion is smaller than the thickness of the first electrode active material layer, and in the wound electrode assembly, the one surface of the first electrode core body is arranged to be oriented toward a winding center side of the wound electrode assembly. a strip-shaped first electrode plate having a plurality of first electrode tabs; a strip-shaped second electrode plate having a different polarity from that of the first electrode plate; a flat-shaped wound electrode assembly obtained by winding the first electrode plate and the second electrode plate with a strip-shaped separator therebetween; and a first electrode current collector connected with the plurality of first electrode tabs laminated, wherein the first electrode plate has a first electrode core body made of metal and a first electrode active material layer formed on the first electrode core body, and on a first end side of the first electrode plate on which the plurality of first electrode tabs are provided, a first protrusion protruding in a thickness direction of the first electrode core body from one surface of the first electrode core body is formed on the one surface of the first electrode core body except where the plurality of first electrode tabs are, a protrusion protruding in the thickness direction of the first electrode core body from the other surface of the first electrode core body is not formed on the other surface of the first electrode core body, or a second protrusion protruding in the thickness direction of the first electrode core body from the other surface of the first electrode core body and having a smaller protrusion height than a protrusion height of the first protrusion is formed on the other surface of the first electrode core body, the protrusion height of the first protrusion is smaller than the thickness of the first electrode active material layer, and in the wound electrode assembly, the one surface of the first electrode core body is arranged to be oriented toward a winding center side of the wound electrode assembly.