A microwave plasma processing apparatus includes a microwave supply part configured to supply a microwave; a microwave emission member provided on a ceiling of a process chamber and configured to emit the microwave supplied from the microwave supply part; and a microwave transmission member configured to close an opening provided in the ceiling and made of a dielectric substance that transmits the microwave transmitted to a slot antenna. The ceiling has at least two recesses provided on an outer side of the opening, each of the at least two recesses having a depth different from each other.