A magnetron sputtering apparatus includes a cathode electrode having a first surface and a second surface opposite to the first surface, a target attachable to the first surface of the cathode electrode, and a magnet unit which is adjacent to the second surface of the cathode electrode and forms a magnetic field on the target surface. The magnet unit includes a plurality of magnet pieces each having a first magnet member which is magnetized in a direction perpendicular to the target and is arranged with a magnetic pole end face oriented toward the target, and a second magnet member which is magnetized opposite to the first magnet member in the direction perpendicular to the target and is arranged in contact with the first magnet member with a magnetic pole end face being oriented toward the target.