To obtain a stable thickness without a break in the course of cutting with regard to the manufacturing method of a spiral fin for manufacturing a spiral fin made by forming a fin body in a spiral shape, and the spiral fin itself.

A spiral fin 19 is obtained by continuously cutting a solid bar 15 as turning the bar 15 by feeding a bite 17 so that a core 15a may remain in the center of the bar 15 and continuously cutting the bar 15 as bring the cutting edge 17a of a bite 17 into contact with the bar 15 in a specific contact angle θ.