Air flow controller and manufacturing method of stretched film

A manufacturing apparatus for a stretched film, wherein:

• the manufacturing apparatus comprises an air flow controller and a tenter oven,
• the air flow controller includes a box-shaped body cover that is disposed above and/or below a film running surface to be adjacent to an upstream side of an entrance of the tenter oven in a film running direction and/or a downstream side of an exit of the tenter oven in the film running direction,
• the tenter oven includes the entrance into which a film is conveyed and the exit from which the film is taken out, and the tenter oven has a preheating process, a stretching process, a thermal fixation process and a cooling process,
• the box-shaped body cover extends in the film running direction and has a surface facing the film running surface and being open,
• the box-shaped body cover includes at least one partition structural body in the box-shaped body cover, the partition structural body extends in a width direction of the film and separates inside of the box-shaped body cover into a plurality of chambers, and
• each of at least two of the chambers is provided with an air discharge mechanism configured to discharge air in a corresponding chamber.