An antenna unit includes a feeding component 40 and a metal plate 50 on which the feeding component 40 is mounted. The feeding component 40 has an attaching member 43 made of resin to support a feeding line against the metal plate. The metal plate 50 has a pair of cut and raised parts 51 at both ends thereof while the attaching member 43 has a pair of locking hooks 432 at both ends thereof. The locking hooks are partly inserted into the cut and raised parts and thereby the feeding component is attached to the metal plate without projecting any parts of the attaching member from a rear surface of the metal plate.