A reactive gas application apparatus including an instrument (10) which includes: a plasma generating unit (12)； and an outlet (1a) for blowing out a reactive gas activated by plasma, the plasma generating unit (12) including: a tubular dielectric (3) to which a plasma generation gas is introduced； an inner electrode (4) provided inside the tubular dielectric (3), and extending in a tube axis direction (O1) of the tubular dielectric (3)； and an outer electrode (5) provided outside the tubular dielectric (3) and faces the inner electrode (4) through the tubular dielectric, wherein the inner electrode (4) has a shaft portion extending in the tube axis direction and a spiral ridge formed on an outer peripheral surface of the shaft portion.
