Abstract: An apparatus includes an optical pick-up unit (OPU) and a controller. The OPU is used for irradiating light beam to the optical disc. The controller is used for driving the optical pick-up head to apply a plurality of first predetermined erasing powers to a first data area and a plurality of second predetermined erasing powers to a second data area. A first optimum erasing power and a second optimum erasing power are obtained respectively by ascertaining an optical property of the optical disc. The first optimum erasing power and the second erasing power are used for erasing data stored in different areas of the optical disc.