Abstract: An object is to provide a plasma film forming apparatus capable of reducing particles even in the case in which a film is formed by applying a bias to a substrate. In the plasma film forming apparatus in which a bias is applied to a substrate (5) placed on a supporting table (4) in a chamber and forming a thin film on the substrate (5) by using plasma, the supporting table (4) has a columnar supporting table main body (4b) having a contact surface in contact with the substrate (5), the contact surface (4a) having an outer diameter (c) smaller than an outer diameter (W) of the substrate (5); and a flange portion (4c) extended in an outer circumferential direction from a side surface (4d) of the supporting table main body (4b); wherein a predetermined first gap (G1) is formed between the flange portion (4c) and a rear surface of the outer circumference of the substrate (5).