To provide a winding-up method of a flat and smooth film and a film roll preventing generation of grain-like protuberance defects in a surface layer and a winding core portion of the film roll.

A method of manufacturing the film roll of a length equal to or more than 300 m that is obtained by the following processes (I) to (III), and the film roll are provided. In the process (I), a film is sent out from a supply source 1. In the process (II), the sent film 13 is wound around a grooved roller 9 at surface pressure 10-100 kg/m and then the film is slit on the roller. Wherein (1) the roller has separate grooves successive in a circumferential direction in a roller outer peripheral surface, (2) a groove width B1 measured in an axial direction of the roller outer peripheral surface is 1-10 mm, (3) the plurality of grooves of the roller are provided in the axial direction and a pitch P is 2-20 mm, and (4) a groove depth D is 0.2-10 mm. In the process (III), the slit film is wound at a winding speed equal to or faster than 150 m/min.