dented portion faces for example an area extending from the outer circumferential surface of the rotation table 2 to a bottom surface part 14 in the dented portion the areas with pressure communication between the first and second process areas 91 92 are referred to as first and second evacuation areas e 1 and e 2 respectively accordingly as illustrated in fig1 and 3 first and second evacuation ports 61 and 62 are formed at corresponding bottom parts of the first and second evacuation areas e 1 and e 2 as illustrated in fig1 the first evacuation port 61 is connected to for example a vacuum pump first evacuation part 64 a via a first evacuation channel 63 a a first valve 65 a is interposed between the first evacuation channel 63 a and the vacuum pump 64 a the first valve 65 a includes for example an apc auto pressure controller that can change the opening degree in which the first valve 65 a is opened the flow rate of the gas flowing in the first evacuation channel 63 a can be adjusted in correspondence with the opening of the first valve 65 a a first process pressure detecting part 66 a is connected to an upstream side of the first valve 65 a towards the chamber 1 a first pressure detecting part 67 a is connected to a downstream side of the first valve 65 a towards the vacuum pump 64 a.