Abstract: An index card for mounting on a casing for accommodating a recording medium includes a contact type or non-contact type IC for storing information or for processing signals.

Abstract: Insertion and removal of an index, which is interposed between a disk tray and a case half in which the disk tray is fitted, is facilitated in a disk housing case. The disk housing case is constituted by: a disk tray; and first and second case halves for housing the disk tray. The index is interposed between the disk tray and the second case half. An index entry/exit opening is provided at an end at which the case halves are linked, or at an end opposite the link end. Contact openings, for enabling a finger or an index sliding member to contact the index to insert and remove the index, are provided in the disk tray and/or the second case half.