A disc apparatus in which recorded data can be correctly reproduced despite occurrence of a low-reliability area at a specified position on a disc on which synchronization signals are recorded. A comparison error signal between the playback RF signals read out from a disc 100 and channel clocks PLCK enters a VCO 15 via a phase/frequency comparator 12. A VCO 15 generates PLCK at a frequency corresponding to the voltage of the comparison error signal. A data detection unit 16 takes out data from the playback RF signals. If a Sync pattern detection interpolation unit 17 detects the Sync pattern correctly from this data, the above comparison error signal is directly fed to the VCO 15 and, if otherwise, the sample-and-hold unit 14 holds the voltage of the comparison error signal by control signals from a controller 20. At this time, interpolation of the Sync patterns by the Sync pattern detection interpolation unit 17 is discontinued.