A wireless charging device includes a plug module, a rack and a wireless charger. The plug module has a top wall, and two opposite side walls connected with two opposite sides of the top wall. A front end of a top surface of the top wall of the plug module is defined as an inclined plane. The rack is mounted on the inclined plane of the plug module. A front end of a bottom surface of the rack is recessed inward to form a lower accommodating groove. The inclined plane is mounted in the lower accommodating groove. A top surface of the rack is recessed downward to form an upper accommodating groove. The wireless charger is mounted in the upper accommodating groove.