The present invention is to detect an envelope defect of a read signal due to a fingerprint on a surface of a disc, an inter-layer interference of a dual disc, or the like which is a factor of a read error of an optical disc, and is to improve a read capability of an optical disc drive while avoiding a read error by performing an appropriate processing. Means for detecting an envelope defect and means for counting the number of appearances of the envelope defect are included in the present invention. A read condition for factors of a read error is set at the time of a read retry, and a read condition suitable for the decoding of a readout signal containing an envelope defect is set at the time of detection of the envelope defect in the present invention.