A plasma processing apparatus includes a worktable in a process chamber to horizontally place a target substrate thereon. A plasma generation space is defined above and around the worktable within the process chamber. The plasma generation space includes a peripheral plasma region and a main plasma region respectively located outside and inside an outer edge of the target substrate placed on the worktable. The apparatus further includes a magnetic field forming mechanism configured to form first, second, and third magnetic fields within the peripheral plasma region. The first magnetic field includes magnetic force lines extending along a vertical first cylindrical plane. The second magnetic field includes magnetic force lines extending along a vertical second cylindrical plane located inside the first cylindrical plane. The third magnetic field includes magnetic force lines extending along vertical radial planes located between the first and second cylindrical planes.