A disc balancing device and a method thereof. The disc balancing device includes a disc assembly having a driving source, and a disc rotatably disposed at the driving source, a displacement measurement unit measuring vibration in the rotation of the disc assembly, a phase angle measurement unit measuring a phase angle from a reference point of the disc assembly in the rotation of the disc assembly, an operation/control unit calculating an eccentric mass and an eccentric position of the disc assembly, by using the biased vibration measured in the displacement measurement unit and the phase angle measured in the phase angle measurement unit, and a laser cutter tracking and laser-cutting the side portion of the disc corresponding to the eccentric position according to the information from the operation/control unit, whereby the eccentric mass of the disc assembly is balanced to reduce vibration in the rotation.