To solve the problem of not yet provided with a run-out preventing and guiding mechanism having no fear of damage, simultaneously realizing the run-out preventing action and the guiding action of the lower side, in a suspended sliding door widely used at present for the doorway of prefabricated and other various kinds of freezing/refrigerating warehouses, which is a suspension type, with a the lower side free, and particularly, of a large shape and heavy weight.

While installing a guide rail 5 on the storage body 1 side such as the freezing/refrigerating warehouse, a guide piece 8 is installed on a bracket 7 installed on the door 3 side so as to slide or fall off by preset external force, and a door 3 is smoothly opened and closed without run-out by the action of the guide piece 8 usually engaging with the guide rail 5. When a large load not less than the preset external force is once applied to the door 3, the guide piece 8 slides in the bracket 7, or slidingly falls off from the bracket 7, so that a door side and storage body side mechanism is not wholly damaged.