A film deposition apparatus configured to perform a film deposition process on a substrate in a vacuum chamber includes a turntable configured to rotate a substrate loading area to receive the substrate, a film deposition area including at least one process gas supplying part configured to supply a process gas onto the substrate loading area and configured to form a thin film by depositing at least one of an atomic layer and a molecular layer along with a rotation of the turntable, a plasma treatment part provided away from the film deposition area in a rotational direction of the turntable and configured to treat the at least one of the atomic layer and the molecular layer for modification by plasma, and a bias electrode part provided under the turntable without contacting the turntable and configured to generate bias potential to attract ions in the plasma toward the substrate.