In a vehicle steering transmission device, a first gear is rotatable on a rotational axis to rotate in accordance with a vehicle steering operation, a second gear is rotatable on the rotational axis and connectable to a vehicle wheel so that an orientation of the vehicle wheel is changed, an intermediate gear engages with the first and second gears, a support member is rotatable on the rotational axis while supporting the intermediate gear in such a manner that the intermediate gear is rotatable on another rotational axis which another rotational axis intersects the rotational axis and extends perpendicularly to the rotational axis, and a driving device drives the support member to rotate on the rotational axis so that a differential rotational motion is generated between the first and second gears.