The object of the invention is to provide a plasma processing apparatus having enhanced plasma processing uniformity. The plasma processing apparatus comprises a processing chamber 1, means 13 and 14 for supplying processing gas into the processing chamber, evacuation means 25 and 26 for decompressing the processing chamber 1, an electrode 4 on which an object 2 to be processed such as a wafer is placed, and an electromagnetic radiation power supply 5A, wherein at least two kinds of processing gases having different composition ratios of O2 or N2 are introduced into the processing chamber through different gas inlets so as to control the in-plane uniformity of the critical dimension while maintaining the in-plane uniformity of the process depth.