A method for producing a magnetic tape and method for improving a winding form of the magnetic tape are provided. These methods comprises a stage for winding a magnetic tape around a tape reel; and a stage for thermally treating the magnetic tape wound around the tape reel under preset thermal treatment conditions to impart the magnetic tape to winding habit. In the winding state, the magnetic tape is wound around a tape reel whose hub circumference is formed into a tapered state in the stage for winding a magnetic tape.