An antenna device for improving antenna performance of a portable terminal having a metal edge installed on a case frame is disclosed. The antenna device includes a main board equipped with a power supply end for supplying power and a ground surface for grounding the main board, a loop radiator connected with the power supply end of the main board at first end and connected with the ground surface of the main board at a second end, and a metal body disposed along an edge of the portable terminal and electrically connected with the ground surface of the main board.