PURPOSE: To manufacture a steering shaft, in particular an upper shaft in the form of a solid round bar in an uncut chip (chipless) manner.

CONSTITUTION: An upper shaft 1 is formed by a cold-forging process for cold- forging the raw material of a solid round bar to form a shaft thin part, a forming process for forming a peripheral groove 4 and a low diameter part 12 swollen in the right and left of the peripheral groove 4 on the shaft thin part by roller forming, and a rolling process for forming a serration 3 on the peripheral surface of the lower diameter part 12.