PURPOSE: To increase the rigidity of a shaft without increasing the diameter thereof so as to reduce its weight by winding a fibrous material having a large modulus of longitudinal elasticity around a metal shaft core having flanges, and sintering it in the form of a structure integrated with the shaft core.

CONSTITUTION: Flanges 1 are provided on a thin shaft core 2, while a fiber 3 having a large modulus of longitudinal elasticity is wound around the shaft core 2 in order to form a plurality of layers to a specified outer diameter D, and then the whole layers are sintered thereto so that the whole of them are integrally formed. It is therefore possible to increased rigidity without increasing a shaft diameter, so as to increase a peculiar torsional oscillation number of the shaft system to the extent that there is no interference with the response speed of a control system, and to reduce its weight.