To provide a plasma film deposition system capable of depositing an electrically conductive film with a uniform film thickness without reducing a film deposition rate.

A gaseous starting material is fed to the space between confronted electrodes, further, voltage is applied to the space between the electrodes to crack the gaseous starting material, and an electrically conductive film 4 is deposited on a substrate 2 passing through the space between the electrodes. The electric field intensity between the electrodes is successively weaken from the inlet side toward the outlet side in the substrate 2. For example, either electrode 20 is divided into a plurality of electrode elements 21 to 24, the voltage to be applied to each electrode element 21 to 24 is suitably changed, and the electric field intensity between the confronted electrodes is made weak almost stepwise as it goes to the latter-half position 29 where the deposition of a film 4 progresses.