A containing device equipped with: a casing formed in a substantially polyhedral shape, the casing having six substantially quadrilateral faces facing mutually different directions; and a containing part formed in the casing, the containing part containing a contained object so as to be insertable/removable. An opening continuous with the containing part, or a peripheral edge part of an opening continuous with the containing part, is disposed at a position corresponding to a first side, which is one of a plurality of sides constituting a polyhedron that corresponds to the casing.