A tread kerf of a snow tire is capable of securing the performance of the tire on a dry road, a wet road, a snowy road, and an icy road, maintaining uniform rigidity of the block, and improving wear resistance. The tread kerf is formed in the outer surface of a tread block of the snow tire in a depth direction of the block in a shape of a polygonal wave extending along the outer surface of the block, wherein the entrance distance of the polygonal wave is less than the bottom distance of the polygonal wave such that side surfaces between the entrance and the bottom of the polygonal wave are formed as inclined surfaces, the distance between which decreases toward the entrance. The polygonal wave is moved in an advancing direction of the polygonal wave while being twisted in the depth direction of the block.