Microwave plasma treatment device

Patent Pending PROBLEM TO BE SOLVED: To provide a treatment device provided with dielectric windows formed by favorably treating surfaces thereof in order to suppress the generation of abnormal discharging caused by a concentration of an electric field, and the usage of the treatment device. ; SOLUTION: This microwave plasma treatment device 10 includes: a treatment vessel 100; the dielectric windows 136a formed on the treatment vessel 100; a gas supply source 144 supplying desired gas into a space of the treatment vessel 100; and a microwave generator outputting microwaves.