Abstract: A surface treatment apparatus generates resonance on a line including an electrode. The surface treatment apparatus has a vacuum container (1) wherein a wafer (4) is stored and vacuum evacuation is made possible; and an upper electrode (3) and a lower electrode (5) arranged to face each other in the vacuum container (1). The surface treatment apparatus is provided with a high frequency power supply (16), which supplies the upper electrode (3) with high frequency power through a matching circuit (17); and a high frequency power supply (18), which supplies the lower electrode (5) with high frequency power through a matching circuit (19). Furthermore, the surface treatment apparatus is provided with a resonance adjusting section (resonance circuit) (60) connected between the lower electrode (5) and the ground; and a treatment gas supplying mechanism (not shown in the figure) for supplying the treatment gas into the vacuum container (1).