A mobile device includes a main circuit board, a PCB (Printed Circuit Board), a feeding connection element, a grounding connection element, a first radiation element, a second radiation element, a third radiation element, a fourth radiation element, and a fifth radiation element. The first radiation element is coupled to the feeding connection element. The second radiation element is coupled to the feeding connection element. The third radiation element is coupled to the grounding connection element. The fourth radiation element is coupled to the first radiation element. The fifth radiation element is coupled to the feeding connection element. The feeding connection element, the grounding connection element, the first radiation element, and the second radiation element are disposed on the main circuit board. The third radiation element, the fourth radiation element, and the fifth radiation element are disposed on the PCB.