To provide a method of forming a thermoplastic resin film having high thickness accuracy, and to provide the thermoplastic resin film.

In the method of forming the thermoplastic resin film, the thermoplastic resin film is formed by inserting a sheet-like molten thermoplastic resin material 3 extruded from a die 2 between two cooling rolls 4, 5. A step 10 having an outside diameter smaller than that of a roll center is formed circumferentially on each outer peripheral surface of both ends of at least one cooling roll in the two cooling rolls 4, 5. When inserted between the two cooling rolls 4, 5, the molten thermoplastic resin material 3 is also inserted between the step 10 and the other cooling roll, and linear pressure received by the molten thermoplastic resin material 3 between the step 10 and the other cooling roll is substantially 0 kgf/cm.