An airfoil having a leading edge and a trailing edge is provided. The airfoil includes a rear cooling path connected to the trailing edge to discharge air to the trailing edge, a plurality of cooling fins formed in the rear cooling path, and a flow guide rod connecting the cooling fins to support the cooling fins, wherein each of the plurality of cooling fins includes an upper fin portion protruding upward from an upper portion of the flow guide rod, a lower fin portion protruding downward from a lower portion of the flow guide rod, and an intermediate fin portion inserted through the flow guide rod.