PURPOSE: To promote the stability of steering, by using two springs of different stiffnesses to push a rack to engage it with a pinion and by applying both the springs to the rack around a straight movement position and applying only the spring of lower stiffness to the rack beyond the vicinity of the position.

CONSTITUTION: A rack 5 is engaged with a pinion 4 coupled to a steering wheel. A support yoke 6 is located in contact with the rear of the rack 5. A plate spring 8 of higher stiffness and a helical spring 9 of lower stiffness are interposed between the rear of the yoke 6 and a yoke plug 7 to push the rack 5 on the pinion 4. The pitch and thickness of the teeth 5a of the rack 5 are constant around the straight movement position of the steering wheel but are gradually reduced beyond the vicinity of the position. The distance between the axes of the pinion 4 and the rack 5 is maximum around the straight movement position and becomes smaller beyond it so that both the springs 8, 9 act to the rack around the position and only the spring 9 acts to the rack beyond the vicinity of the position.