The present invention discloses a vehicle steering system having a rack bar supporting apparatus which prevents the rotation of a rack bar and makes the rack bar supporting apparatus compact by providing a plurality of rack bar supporting apparatuses installed at the rear of the rack bar to support the rack bar in the direction of a pinion gear. The vehicle steering system comprises a pinion shaft having a pinion gear on the outer circumference and being installed within a housing; a rack bar being located within the housing so that it can cross the pinion shaft and having a rack gear meshing with the pinion gear at one side of the middle part; and rack bar supporting apparatus provided on the rear surface of the rack bar for elastically supporting the rack bar in the direction of the pinion shaft, wherein a plurality of the rack bar supporting apparatuses are provided to vary the supporting direction and supporting force for supporting the rack bar.