A disc tray including: a tray frame having a plurality of accommodation portions each of which selectively accommodates one of a plurality of discs having different diameters and at least one guide portion; and at least one holding apparatus coupled to the guide portion and which holds a selectively accommodated disc. A first SC is connected to the BTS and a second SC is connected to the RAE. The bracket device engages with the retainer device. The first and second layer engage in a closed state to prevent air flow there between in a first thermal state and open to allow air flow there between in a second thermal state.