PURPOSE: To make a quality of a product favorable by constituting the title device so that a gap is not formed between a radius of curvature part of a stock guide plate and a calender roll, by a method wherein at least either of the radius of curvature part facing on the calender roll or the inside facing on the central side in an axial direction of the calender roll out of a stock guide plate is formed of an elastic member.

CONSTITUTION: In the case where a radius of curvature part 18b facing on calender rolls 3, 4 of a stock guide plate 18 is formed of an elastic member, the radius of curvature part 18b is expanded by feeding a fluid to a hollow part 18a and the radius of curvature part 18b is brought into contact with the outside circumferential surfaces of the calender rolls 3, 4. With this construction, plastic raw materials M fed to a bank do not leak out of the bank. Then in this case, even if the radius of curvature part 18b is worn, since the radius of curvature part 18b of the stock guide plate 18 is expanded and comes into contact with the calender rolls 3, 4 always, even in the case where the radius of curvature part 18b is worn, leaking of the plastic raw materials M outside of the bank can be prevented reliably.