An easy-to-install Luneberg lens antenna device is constituted by combining a hemispherical Luneberg lens and a radio wave reflector. The Luneberg lens antenna device comprises an antenna fixing jig (2), and a fixing means, e.g., a bolt (3), for fixing the radio wave reflector (1b) of the antenna device (1) removably to the antenna fixing jig (2). The reflector (1b) and the antenna fixing jig (2) are previously provided, respectively, with fixing parts for fixing by the fixing means, the antenna fixing jig (2) is fixed to an antenna installing section and the reflector (1b) is fixed to the antenna fixing jig (2) by the fixing means.