A plasma processing method for processing a sample by applying a high-frequency bias power periodically for each one period (T) which is divided along a time axis into a first sub-period (T1) for which feedback control of a CD gain is executed, a second sub-period (T2) for which feedback control of a select ratio is executed, and a third sub-period (T3) for which feedback control of both the CD gain and the select ratio are executed. The applied power is set at a large value in the first sub-period, and a duty ratio T1/T is controlled in accordance with the CD gain. A plurality of samples are processed with preset process conditions, and feedback control for each processing unit of the samples is executed in accordance with a processing state of each of the samples so that an average applied power over the one period (T) is constant.