PROBLEM TO BE SOLVED: To prevent a waste metal from being deposited on a cutting blade, prevent an aluminum sludge from growing in the cutting blade side and greatly extend a blade life, provide the cutting blade having high sharpness, and successively perform a cutting process without intermittence, thereby improving efficiency of production.SOLUTION: A cutting blade is used for cutting a laminated sheet having a metal foil. The cutting blade has a base substance by a steel material, and the coating comprising a DLC, etc., is formed in at least a cutting edge of the base substance. Also, the cutting edge of the cutting blade is formed with a curvature, and the curvature radius of the cutting edge in the contact point upon starting the cutting of sleeves is formed by 1 time or more and 5 times or less of the curvature radius in the tube. Consequently, the cutting blade for the sleeves is provided for forming a metal laminate tube or a polyfoil tube.
