Abstract: The package mounted to a recording and/or reproducing apparatus with a disk-form recording medium such as a magneto-optic disk, etc. housed is formed with thin a sheet plate member such as a plastic thin sheet, etc., thereby enabling simplification of the construction and reduction of cost. In a housing container (3) equipped with a housing section (2) for housing a disk-form recording medium, a cover (4) formed with a thin plate member for closing the opening of the housing section (2) is joined to form a package (1). To the cover (4), a detaching section (7) is formed at a section opposite at least a part of the recording section of a disk-form recording medium housed in the housing section (2), and the detaching section (7) is detached to form an opening at the cover (4) when the disk-form recording medium is used.