<p>An antenna device reduced in size and increased in bandwidth. The antenna device comprises a first radiating plate and a second radiating plate arranged with a space having a predetermined width. A power supply section feeding a power to the first radiating plate and the second radiating plate is installed in the space. The first radiating plate and the second radiating plate are characterized in that they are similar to each other in plan view shape and different in size from each other.</p>
