Abstract: A hollow tube body for medical tool has a plurality of metallic wires (2) cylindrically stranded to form a flexible tube. An inner surface of the flexible tube forms a convex-concave structure represented by the metallic wires (2) formed semi-circular in corss section. A leading distal end of the flexible tube is formed into a knife-edge circle configuration to provide a knife-edge circle front (3). The hollow tube body is used for catheters (K, K1, K2 and K3) to impart them with a perforative ability so as to improve its quality and performance.