PURPOSE: To obtain a thin film of high quality having a flexible film as a substrate at a low cost, by adhering the flexible film running at the same speed as that of a beltlike member closely to the beltlike member, forming a thin film on the surface of the flexible film while transferring them in vacuum by the sputtering method, etc.

CONSTITUTION: A flexible film 1 and a beltlike member 2 consisting of a metal or plastic, etc. are adhered closely by a pressing roll (6c) to form a laminated member 3, which is then introduced into a vessel 7 having a thin film forming means, e.g. the sputtering or vapor depositing method, and slid on a hot plate 9 at a controlled temperature under reduced pressure to deposit a material, e.g. Co, Fe or Si, capable of exhibiting the function on one side of the flexible film 1 while transferring them. Thus, the aimed thin film is formed. An endless beltlike member may be revolved in a system for running the beltlike member 2.

EFFECT: The temperature control can be carried out with certainty without applying an excess tension to the flexible film 1.