An antenna is adapted to be mounted on a vehicle body. An antenna base is formed with a first through hole. A first fixing screw is provided with a thread portion adapted to be inserted into a second through hole formed in the vehicle body via the first through hole, and a head portion continued from the thread portion and having a size larger than the second through hole. A receptacle is provided on the antenna base and receiving the head portion such that an axis of the first fixing screw is swingable relative to the vehicle body. A nut is adapted to be fitted with the thread portion so as to clamp the vehicle body together with the head portion.