An arc path formation unit, comprising: a magnet frame having an inner space, and comprising a plurality of surfaces (511, 512, 513, 514) surrounding the inner space; and magnets coupled to the plurality of surfaces to form magnetic fields in the inner space, wherein the plurality of surfaces (511, 512, 513, 514) comprise: a first surface extending in one direction; and a second surface disposed to face the first surface and extending in the one direction, whereby the arc path formation unit is configured to produce a magnetic field in the inner space by: a first magnet disposed on one of the first surface and the second surface; a second magnet disposed on another one of the first surface and the second surface; and a third magnet disposed on the another surface with being spaced apart from the second magnet by a predetermined distance; wherein a first facing surface of the first magnet that faces the second surface has a polarity different from a polarity of a second facing surface of the second magnet and a third facing surface of the third magnet both facing the first surface, characterised in that said first magnet is disposed on a middle portion of one of the first and the second surface; wherein only the first magnet is disposed on one of the first surface and the second surface, wherein only the second magnet and the third magnet are disposed on another one of the first surface and the second surface, and wherein the first magnet faces the second magnet and the third magnet in a diagonal direction toward a front left and a front right with the inner space interposed therebetween. a magnet frame having an inner space, and comprising a plurality of surfaces (511, 512, 513, 514) surrounding the inner space; and magnets coupled to the plurality of surfaces to form magnetic fields in the inner space, wherein the plurality of surfaces (511, 512, 513, 514) comprise: a first surface extending in one direction; and a second surface disposed to face the first surface and extending in the one direction, whereby the arc path formation unit is configured to produce a magnetic field in the inner space by: a first magnet disposed on one of the first surface and the second surface; a second magnet disposed on another one of the first surface and the second surface; and a third magnet disposed on the another surface with being spaced apart from the second magnet by a predetermined distance; wherein a first facing surface of the first magnet that faces the second surface has a polarity different from a polarity of a second facing surface of the second magnet and a third facing surface of the third magnet both facing the first surface, characterised in that said first magnet is disposed on a middle portion of one of the first and the second surface; wherein only the first magnet is disposed on one of the first surface and the second surface, wherein only the second magnet and the third magnet are disposed on another one of the first surface and the second surface, and wherein the first magnet faces the second magnet and the third magnet in a diagonal direction toward a front left and a front right with the inner space interposed therebetween. a first surface extending in one direction; and a second surface disposed to face the first surface and extending in the one direction, whereby the arc path formation unit is configured to produce a magnetic field in the inner space by: a first magnet disposed on one of the first surface and the second surface; a second magnet disposed on another one of the first surface and the second surface; and a third magnet disposed on the another surface with being spaced apart from the second magnet by a predetermined distance; wherein a first facing surface of the first magnet that faces the second surface has a polarity different from a polarity of a second facing surface of the second magnet and a third facing surface of the third magnet both facing the first surface, characterised in that said first magnet is disposed on a middle portion of one of the first and the second surface; wherein only the first magnet is disposed on one of the first surface and the second surface, wherein only the second magnet and the third magnet are disposed on another one of the first surface and the second surface, and wherein the first magnet faces the second magnet and the third magnet in a diagonal direction toward a front left and a front right with the inner space interposed therebetween. a first magnet disposed on one of the first surface and the second surface; a second magnet disposed on another one of the first surface and the second surface; and a third magnet disposed on the another surface with being spaced apart from the second magnet by a predetermined distance; wherein a first facing surface of the first magnet that faces the second surface has a polarity different from a polarity of a second facing surface of the second magnet and a third facing surface of the third magnet both facing the first surface, characterised in that said first magnet is disposed on a middle portion of one of the first and the second surface; wherein only the first magnet is disposed on one of the first surface and the second surface, wherein only the second magnet and the third magnet are disposed on another one of the first surface and the second surface, and wherein the first magnet faces the second magnet and the third magnet in a diagonal direction toward a front left and a front right with the inner space interposed therebetween.