PURPOSE: To change the steering gear ratio according to the traveling condition of a vehicle, to simplify the system, to miniaturize the device, to improve the mountability, and to reduce the cost.

CONSTITUTION: A steering device 10 for a vehicle is provided with a first bevel gear 1 6 connected to a steering wheel 26, and a second bevel gear 28 to be turned by a motor 32, and a carrier 34 engaged with a steering rod 14 between the gears is turnably and concentrically supported A third bevel gear 40 is turnably supported on the carrier 34, and jointly engaged with the first bevel gear 16 and the second bevel gear 28. The revolution of the third bevel gear 40 (rotation of the carrier 34) is changed by turning the second bevel gear 28 when the first bevel gear 16 (steering wheel 26) is turned, and the steering gear ratio is changed.