Disclosed is a plasma processing apparatus including: a processing container that defines a processing space; a microwave generator that generates microwaves for plasma excitation; a dielectric having a facing surface that faces the processing space; a slot plate provided on a surface of the dielectric opposite to the facing surface and formed with a plurality of slots that radiate the microwaves to the processing space through the dielectric; and a conductor pattern that is provided on the facing surface of the dielectric and converges an electric field corresponding to the microwaves radiated from each of the slots.