A method of manufacturing an easy open end includes the steps of using a laminated steel sheet with resin films formed on both surfaces of the laminated steel sheet, and forming a panel structure and a score. A score die used for forming the score includes a scoring edge having a cross section in which a tip is a curve and two sides with the tip interposed therebetween are tangent to the curve. The tip is the curve having a curvature radius ranging from 0.2 to 0.4 mm, and the two sides have elevation angles θ in a range of 0.3≦tan θ≦1.0 to an end surface. The panel structure is formed by a motion that is synchronous with a motion in which the score die is pressed to a surface of the laminated steel sheet during the formation of the score.