PURPOSE: To improve the characteristics of actuating force for a steering wheel, by constituting a steering shaft with a first shaft, a second shaft and a sleeve connecting both shafts, and by driving a servo-motor in association with the vertical displacement of the sleeve.

CONSTITUTION: A second shaft 3 is arranged in line with a first shaft 2 attached to a steering wheel 1, and is connected with a joint sleeve 6 integrally rotatable with the shaft 3 and vertically slidable. A stepped shaft 8 which is slidably fitted in the above-mentioned sleeve 6, is fixed to the first shaft 2, and is formed with skew grooves 7 in the peripheral part thereof. Further, rollers 9 slidably fitted in the skew grooves 7 are journalled to the inside of the sleeve 6. Further, an electrical detector 13 detects the axial displacement of the sleeve 6 and therefore, delivers an output signal in order to drive a servo-motor 14 for rotating the second shaft 3.