An antenna device, a radio communication terminal, an external antenna, and a hand strap can be provided, which are capable of ensuring satisfactory communication performance without being affected by the surrounding environment even in an area where the electric field is weak, and having the antenna performance improved by slightly modifying the body of an existing radio communication device. The antenna device according to the present invention includes an internal antenna (2) electrically connected to and incorporated into a circuit for radio communication within a case (1) and an external antenna (3) externally attached to the case.