PURPOSE: To reduce a steering force during running at a low speed and to prevent excessive steering of a steering wheel during running at a middle and a high speed, by a method wherein a multi-stage reduction gear is located between a steering wheel and a steering gear, and a gear ratio is changed according to a car speed.

CONSTITUTION: A 2-step reduction gear 20 is situated between a steering shaft 9, to which a steering wheel 8 is secured, and an input shaft 10 of a steering box incorporating the steering shaft 9 and a steering gear. The 2-step reduction gear 20 is formed such that inner tooth gears 18 and 19, which have a number of projections 23 and 24, respectively, on their outer peripheries and can be fixed, are selectively fixed by a selector 31 to provide for different reduction ratios. The selector 31 has a select arm 29 which is swung through a control rod 27 with the aid of an electromagnetic solenoid 25, and when a car speed detected by a car speed sensor 41 exceeds a set value, the solenoid 25 is controlled by a controller 40 so that the select arm 29 is engaged with a projection 24, and this reduces a reduction ratio.