The present invention provides a kerf structure for a snow tire, including unit structures on each of which spiral-shaped protrusions are continuously formed to be spaced a predetermined distance apart on the outer circumferential surface of a semi-cylindrical shaped column, wherein the continuously formed unit structures are arranged by alternating convex and concave portions in a zigzag formation, which is capable of optimizing the rigidity which can maintain gripping force as an original function of a kerf while ensuring a friction force generated from small blocks of a tread portion partitioned with kerfs by collapsing a block at an optimum level and further ensuring the kerf function on snow even in the last stages of tread wear by lowering the rigidity of the blocks of the tread portion.