PURPOSE: To continuously form a deposited film with good uniformity by constituting side walls to be exposed to microwave plasma and forming the deposited film on a continuously moving band-shaped member.

CONSTITUTION: The band-shaped member 101(A) is moved and a magnetic material 106(A) is brought into tight contact with the rear surface of the band- shaped member 101(A) during the course of this movement to curve the band- shaped member 101(A) attracted by magnetic fields. A columnar film forming space is formed of the band-shaped member 101(A) in such a manner. Gaseous raw materials for forming the deposited film are introduced therein via a gas supplying means 112(A). Microwave energy is simultaneously radiated to induce microwave plasma in a film forming space by a microwave applicator for radiating the microwave energy. The side walls to be exposed to the microwave plasma are constituted and the deposited film is formed on the surface of the continuously moving band-shaped member 101(A). The film characteristics and the stability of the film characteristics are improved in this way.