To provide a disk sending medium which is simply and easily assembled storing a 12 cm disk, and which can be sent as standard sized first class mail at 90 yen protecting the disk from damage during mailing in a three-layer box-shaped structure formed by using and assembling corrugated cardboard.

This disk sending medium comprises a front cover 1 conforming to the standard sized first class mail, disc holding parts 2, 2a having an adhesive area on both faces, and a back cover 3. Before assembly, the front cover 1, the holding parts 2, 2a, and the back cover 3 are continuous one sheet. The continuous sheet is folded at the folding parts at the front cover 1, the holding parts 2, 2a, and the back cover 3 to form it into a three-layer box-shaped structure for conforming to the standard sized first class mail.