Vacuum processing apparatus

A magnet unit for a magnetron sputtering apparatus is disposed above the target has: a yoke made of magnetic material and is disposed to lie opposite to the target; and plural pieces of magnets disposed on a lower surface of the yoke, wherein a leakage magnetic field in which a line passing through a position where the vertical component of the magnetic field becomes zero is closed in an endless manner, is caused to locally act on such a lower space of the target as is positioned between the center of the target and a periphery thereof, the magnet unit being driven for rotation about the center of the target. In a predetermined position of the yoke there is formed a recessed groove in a circumferentially elongated manner along an imaginary circle with the center of the target serving as a center.