Abstract: The present invention provides a plasma treatment apparatus which has a plurality of UR-type plasma guns including reflected electron return electrodes, and can stably form a film having uniform film thickness and film quality. A plasma treatment apparatus according to one embodiment of the present invention sets an electric potential of at least one UR-type plasma gun at a floating potential. In one embodiment of the present invention, all UR-type plasma guns may be set at floating potentials. In other embodiment of the present invention, only one UR-type plasma gun may be grounded, and the other UR-type plasma guns may be set at floating potentials.