An antenna device for a portable terminal, which includes an antenna module disposed in an antenna jack of a terminal capable of TV service, the antenna module receiving broadcasting signals depending on mounting/demounting of an external antenna. The antenna device for a portable terminal includes an antenna module disposed along the outer circumference of the antenna jack, which receives broadcasting signals depending on mounting/demounting of the external antenna; an insulator module; and an antenna switch module. The external antenna provides a broadcast signal to the terminal when connection jack of the external antenna is joined with the antenna jack. The antenna module provides broadcast signals when the connection jack external antenna is separated from the antenna jack.