A bellows comprising: a first flat part having a flat cylindrical shape; a second flat part having a flat cylindrical shape and disposed opposite to the first flat part ; and a plurality of corrugated portions , wherein each of the corrugated portions has a tweezers shape and is disposed between the first flat part and the second flat part , and the plurality of corrugated portions are sequentially connected to each other, characterized in that each corrugated portion comprises: a protrusion portion having a first surface and a second surface successively provided next to the first surface in parallel, in which the first surface and the second surface are in close contact with each other, and a connecting portion of the first surface and the second surface protrudes in a circular shape; a convex portion having a third surface extending from the first surface and protruding outward in a convex shape and a fourth surface extending from the second surface and protruding outward in a convex shape; and a concave portion having a fifth surface extending from the third surface and recessed inward in a concave shape and a sixth surface extending from the fourth surface and recessed inward in a concave shape, and the corrugated portions are connected to each other at the concave portion. a first flat part having a flat cylindrical shape; a second flat part having a flat cylindrical shape and disposed opposite to the first flat part ; and a plurality of corrugated portions , wherein each of the corrugated portions has a tweezers shape and is disposed between the first flat part and the second flat part , and the plurality of corrugated portions are sequentially connected to each other, characterized in that each corrugated portion comprises: a protrusion portion having a first surface and a second surface successively provided next to the first surface in parallel, in which the first surface and the second surface are in close contact with each other, and a connecting portion of the first surface and the second surface protrudes in a circular shape; a convex portion having a third surface extending from the first surface and protruding outward in a convex shape and a fourth surface extending from the second surface and protruding outward in a convex shape; and a concave portion having a fifth surface extending from the third surface and recessed inward in a concave shape and a sixth surface extending from the fourth surface and recessed inward in a concave shape, and the corrugated portions are connected to each other at the concave portion. a protrusion portion having a first surface and a second surface successively provided next to the first surface in parallel, in which the first surface and the second surface are in close contact with each other, and a connecting portion of the first surface and the second surface protrudes in a circular shape; a convex portion having a third surface extending from the first surface and protruding outward in a convex shape and a fourth surface extending from the second surface and protruding outward in a convex shape; and a concave portion having a fifth surface extending from the third surface and recessed inward in a concave shape and a sixth surface extending from the fourth surface and recessed inward in a concave shape, and the corrugated portions are connected to each other at the concave portion. <EOS>