A wireless power charging system includes a reception coil unit including an insulating layer, a first coil including a first body portion disposed as a spiral on one surface of the insulating layer and a first lead portion extending from one end of the first body portion and led out of the insulating layer, and a second coil including a second body portion formed on the other surface of the insulating layer and electrically connected to the other end of the first body portion through a via and a second lead portion extending from the second body portion and led out of the insulating layer. The second coil has a width larger than that of the first coil and has a thickness smaller than that of the first coil.