To obtain a TAC film containing no foreign substance of a mat agent.

A raw material dope 27 is prepared from TAC, a solvent and the like. An ultraviolet absorber solution 71 and a mat agent liquid 76 are also prepared. The liquid 27, 71 and 76 are mixed and then homogenized with a static mixer 56 to produce a dope for solvent casting. The dope for solvent casting is sent to a solvent casting die 43 via a flexible pipe 57. The flexible pipe 57 is formed of PTFE having a variation of a cross sectional area of ±5%, a maximum height Ry of surface roughness of not more than 2 μm and a length of not more than 2,500 mm. A solvent cast film 86 is made by casting the dope for solvent casting from a solvent cast die 43 on a solvent cast band 46. The TAC film 102 is obtained by peeling the solvent cast film 86 from the solvent cast band 46.