A composite structure includes a stepped portion formed by laminating a plurality of plies with end surfaces thereof being shifted from each other. The composite structure includes a body portion which includes a first structure portion where a first ply is laminated on a top layer of the first structure portion, a second structure portion where a second ply is laminated on a top layer of the second structure portion, and the stepped portion disposed between the first structure portion and the second structure portion, the second ply being positioned at a distance from the first ply in a lamination direction, and a first cover ply which includes a covering portion covering the stepped portion, one end portion, and the other end portion and is formed so as to cover only a part of a surface of the first ply or a part of a surface of the second ply.