There is provided a plasma processing apparatus comprising: a plasma processing chamber having an upper wall, a sidewall, and a lower wall and having therein a plasma processing space; and a magnetic shield disposed around an outer side of the sidewall and having an opening at an upper side thereof. On the assumption that an angle between a line that passes through a midpoint of an inner surface of the upper wall on the plasma processing space side and connects end points of the opening and the inner surface is θ[°] and a product μi×t of an initial relative permeability μi of a magnetic material forming the magnetic shield and a thickness t[m] of the magnetic shield is Pmc[m], the angle θ[°] satisfies a condition θ>764×Pmc−2+179×Pmc−1+21.3.