A repetitive control apparatus for use in processing a servo signal, wherein a memory (7) is used as a delay element of a filter (6), and a clock signal, which has a frequency that is an integer multiple of the operation frequency of a drive signal, is used to perform a filtering of the filter (6), whereby the gain can be raised without causing a signal, which is to be compensated for, to have a phase rotation, and whereby during recording/reproducing in an optical disc apparatus, a high tracking performance can be achieved for a track position variation caused by a disc geography, such as eccentricity, side-runout or the like. |