The present invention suppresses lowering of the uniformity of plasma treatment for an object to be treated. A first mounting table (2) mounts a wafer W to be subjected to plasma treatment. An elevation mechanism (120) lifts a focus ring (5) mounted around the wafer W. The acquiring unit acquires status information measuring a state of the wafer W. A calculation unit calculates a height of the focus ring (5), whose positional relationship between the upper surface of the wafer W and an upper surface of the focus ring (5) is a predetermined distance, based on the state of the wafer W indicated by the acquired status information. An elevation control unit controls the elevation mechanism (120) so that the focus ring (5) has the calculated height.
展开▼
