The present invention discloses an antenna including a frame body and a circuit board arranged in the frame body. The frame body includes a middle frame and an outer metal frame surrounding the edge of the middle frame and connected to the middle frame. The outer metal frame includes a first side frame, a second side frame, a third side frame and a fourth side frame. The circuit board is provided with a feeding part and a switch circuit which are electrically connected with the third side frame. The third side frame and the middle frame are arranged at an interval to form a first gap; a second gap is arranged between one end of the second side frame near the third side frame and the middle frame. BY virtue of this configuration the radiation efficiency of the antenna is accordingly improved.