A balloon catheter has an elongated flexible shaft made of a metal and at least one inflatable balloon mounted on a distal end area of the flexible shaft. A wall of the shaft providing the mechanical properties for flexibility and pushability is entirely made of metal, the wall has a sheet-like shape, and the wall has an outer diameter up to 0.5 mm and a wall thickness in a range from 0.02 mm to 0.1 mm.
