PURPOSE: To cause a covering mechanism to project/retreat so as to cover the lower section of a door, while a horizontal state is maintained from the lower end of the door by light pushing operation by forming an inclined plane to both or either one of an abutting member with a pushing mechanism or an abutting member with the covering mechanism while both abutting members are brought into contact and fitted.

CONSTITUTION: An abutting state between the abutting member 11 of a rod 10 for a pushing mechanism A assembled into a door D and a vertical frame 84 is released when the door D is opened. The abutting member 11 receives the action of a compression coil spring 12, and is projected to the outside. A covering mechanism B simultaneously receives the action of a compression coil spring 52 and is drawn back upwards corresponding to the space produced by the movement of the inclined plane 20d of an abutting member 20. A shielding tool 50 is drawn into a groove 72, and the door D is opened smoothly and surely in the state in which abutting with the surface of the vertical frame 84 of the rod 10 is released completely. Accordingly, a covering device is pushed down easily by light pushing operation, and a clearance between the door D and a floor F can be covered.