a magnet frame having a space part, in which a fixed contactor and a movable contactor are accommodated, formed therein;

a Halbach array located in the space part of the magnet frame and configured to form a magnetic field in the space part,

wherein a length of the space part in one direction is formed to be greater than a length thereof in the other direction,

the magnet frame includes:

a first surface and a second surface which extend in the one direction, are disposed to face each other, and are configured to surround a portion of the space part; and

a third surface and a fourth surface which extend in the other direction, are continuous with the first surface and the second surface, respectively, are disposed to face each other, and are configured to surround a remaining portion of the space part, and

the Halbach array includes a plurality of blocks disposed side by side in the other direction and in contact with at least one other block of the plurality of blocks and formed of a magnetic material, and is disposed adjacent to one or more surfaces of the third surface and the fourth surface.