A plasma processing device is able to positively enhance a process-gas exhaust efficiency in a processing region and restrict plasma leaking. A processing container of a magnetron type parallel plate plasma processing device has a separator for separating the inside of the processing container into a processing region and an exhaust region. The separator has a plurality of gas passage holes to establish communication between the processing region and the exhaust region, and consists of a non-conductive member. A conductive member is disposed on a gas passage-side surface facing the gas passage holes. A voltage V is applied by a power supply to the conductive member so that the gas passage-side surface is at a potential higher than that of a processing-region surface.