A mobile device includes a supporting element, a ground element, and an antenna structure. The antenna structure includes a first feeding radiation element, a second feeding radiation element, a first parasitic radiation element, a second parasitic radiation element, and a third parasitic radiation element. The first feeding radiation element and the second feeding radiation element are both coupled to a signal feeding point. Each of the first parasitic radiation element, the second parasitic radiation element, and the third parasitic radiation element is coupled to the ground element. A first coupling gap is formed between the first parasitic radiation element and the first feeding radiation element. A second coupling gap is formed between the second parasitic radiation element and the first feeding radiation element. A third coupling gap is formed between the third parasitic radiation element and the second feeding radiation element.