A plasma processing apparatus includes an impedance matching circuit, a balun having a first unbalanced terminal connected to the impedance matching circuit, a grounded second unbalanced terminal, a first balanced terminal and a second balanced terminal, a grounded vacuum container, a first electrode electrically connected to the first balanced terminal, a second electrode electrically connected to the second balanced terminal, an adjustment reactance configured to affect a relationship between a first voltage applied to the first electrode and a second voltage applied to the second electrode, a high-frequency power supply configured to supply a high frequency between the first unbalanced terminal and the second unbalanced terminal via the impedance matching circuit, and a controller configured to control an impedance of the impedance matching circuit and a reactance of the adjustment reactance.