Abstract: The present invention discloses a thin-type optical disc, which comprises a thin optical disc and an auxiliary adapter. The thickness of the optical disc is smaller than that of the conventional optical disc, so as to save the plastic material used in the production of optical discs. Furthermore, the thin optical disc is necessarily accompanied with the auxiliary adapter of a transparent substrate for reading or writing data. If the thin optical disc is put into a optical disc player or rewriter alone, it will not operate normally. Thus, the behaviors and the rules for reading the thin optical disc can be well managed and controlled.