A storage case includes a main body and a cover member so supported by rotary spindles as to be rotatable with respect to the main body and rotatable between an opening position and a closing position. The cover member includes cartridge holding members, formed on right and left sides thereof, for holding and integrally rotating a cartridge inserted into between the main body and the cover member when the cover member rotates to the opening position. When the cover member is closed, an opening, which permits an insertion of a mini disk from outside, is formed between the main body and the cover member. The cover member is opened, whereby the mini disk encased in the storage case also rotates, and hence, even when an index card is disposed between, e.g., the mini disk and the main body, the index card can be taken out without pulling out the mini disk.