PURPOSE: To improve a cooling efficiency and facilitate high speed forming of a T-die film forming apparatus which is equipped with a cooling roll and an air- knife by providing a cooling pipe and an auxiliary air-knife to a T-die exit and to the side opposite to the cooling roll and the air-knife respectively.

CONSTITUTION: An inside surface 13 of a melted film 12 extruded from a T-die 11 touches a cooling pipe 15 which is provided immediately below the T-die and cools the side of the film 12 opposite to the side cooled by a cooling roll and an outside surface of the film 12 is cooled by an air blasted by an auxiliary air- knife 16. The outside surface of the melted film 12 touches the cooling roll 17 and the inside is cooled by an air blasted by an air-knife 18 and then the film 12 is taken up. With this constitution, high speed forming can be realized even if a small apparatus is used and the productivity is significantly improved.